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Print Production – Answer Bank

This was made for referential purposes.
This is not official, but made from collaborating questions from multiple textbooks, and even Wikipedia.
Printing of this file cannot be allowed due to legal reasons.
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What are the stages involved in print production?

Most mass printing done today uses the offset printing technique. Offset printing involves a series of rollers that transfer ink from one to another and finally to the paper. Offset printing is cost effective when printing large amounts of copies, around 5000 or more. When such large quantities are not needed offset printing would prove too expensive; in these cases digital printing would be a better option. Inkjet, laser and solid ink printers are all digital printing technologies, but electrophotography, which uses toner made of carbon powder, is the cheapest alternative.

Pre-Press

Prepress is the term used in the printing and publishing industries for the processes and procedures that occur between the creation of a print layout and the final printing. This procedure includes the manufacture of a printing plate, image carrier, ready for mounting on a printing press, as well as the adjustment of images, photographs and texts or the creation of a high-quality print file. In today’s prepress, either a PDF or native application files are created from programs such as Adobe Creative Suites, QuarkXPress, etc.

Prepress includes all the steps that occur before the actual printing. Prepress usually consists of three steps: composition (writing, formatting, and pagination), reproduction of graphics, and the assembly of all the written and graphical elements into the page layout. Once these steps have been completed the material can be transferred to the films and plates that will be used for printing.

Computers have made the prepress process easier than it has ever been. Now anyone with a word processor can perform the work that required a lot of professionals, years ago. Technological advances have also made it possible to transfer the information and graphics directly from the computer to the printing plates, bypassing the need for films, which eliminated yet another middleman from the production process

Press

The next phase of the production process is transferring the information to paper. This can be achieved through several types of printing technologies. These technologies can be grouped into four different types depending on how the printing surface transfers the ink into the paper

Whether you have a simple one-color job or a complex four-color piece with aqueous coating, you will receive the same high level of service, quality, convenience, sensitivity to deadlines, and competitive pricing.

Letterpress

Printing

In letterpress printing, the printing surface is raised. The ink sticks to the raised parts and is then pressed against the paper.

Gravure Printing

In gravure printing the printing surface has recessed elements that are filled with ink. The raised flat surface (non-printing surface) is then wiped clean with a blade that removes the excess ink, and then the ink is pressed onto the paper.

Lithography

Lithography uses a flat surface. This surface is treated with water to make it repel ink; the places that are not treated with water (printing surfaces) get covered with ink, which is then transferred to the paper. This technology is the one used for offset printing, the most common printing technique used today.

Screen Printing

The screen printing plate is made of a fine mesh where the non-printing elements are blocked by a stencil, so the ink only gets through the unblocked places to the paper. The ink is then pushed through the mesh with a squeegee or blade onto the paper.

Post Press

After the printing is finished the pages are put together and organized. Depending on the type of binding required different processes will take place to get the final product ready for distribution.

When several pages are printed in the same sheet they are separated by cutting them with a guillotine. The resulting pages are then gathered and collated, which means they are stacked in the proper order. Usually the next step is to cut off the edges of the pages, which makes them all the same size. At this time, the work is ready for binding.

Post-press processes are starting to become automated, but not to the same extent as prepress and printing processes. This can create a bottleneck in the process if the finishing stage is not done as quickly as its preceding stages. The reason why post-press is not completely automated is because of the complexity of the processes which requires more manual intervention


What is Pre-Press? Write stages involved in Prepress.

Prepress is the term used in the printing and publishing industries for the processes and procedures that occur between the creation of a print layout and the final printing. The prepress procedure includes the manufacture of a printing plate, image carrier or form, ready for mounting on a printing press, as well as the adjustment of images and texts or the creation of a high-quality print file. In today’s prepress shop, the form of delivery from the customer is usually electronic, either a PDF or application files created from such programs as Scribus, Adobe InDesign or QuarkXPress.

Stages in Prepress

Composite

Composition deals with only text material. The news or articles that come from various sources may not be in the same typography as ammainted by publication as its style. The composite department has to retype the content after it undergoes editing. Page editors leave instruction for recomposing according to the strength of the news or the space reserved for article and features. Newspaper has its own format that states column width, font palate, sizes of font, colour, weight and posture

The things are saved as formatting options in the publication software such as InDesign or Quarkxpress. But, the number of columns allotment for a news and number of deck a headline should be is instructed by the page editor. Page editors are trained to visualize a page as a layout and can ‘see’ with mind’s eye how news can stand out among surround material. According to this the given instructions are somewhat like

36        2        4        SS        2c

In the above instructions, 36 is the font size, for a two liner headline, extending over four columns and will have Sans Serif typeface. The picture will occupy two columns. The resulting news composing will look like as shown to the right.

This look of the news is visualized by the editor and typography staff has to follow this. The images are not added at this stage in traditional method instead they are added at the assembly stage after undergoing the required processing in reproduction stage. The typography staff prepares such text blocks and forward to assembly section for building the page.

Reproduction Stage

Text & images belong to different type of visuals. Images are bitmap and are a whole body, whereas text is an assembly of characters. We recognize characters by their shape & not the tone but the images or the content in the images is recognized by innumerous tones it uses to build a recognizable image. This is why both the forms are not compatible for the impression method of printing. Below are the two stages of Colour Separation,

Colour Separation

Colour images are made up of nearly sixteen million colours. These colours are proportionate combination of three primary colours, Red, Green and Blue. Breaking down the image into its colour components is called colour separation.

For this the image undergoes filtration through each of the primaries. The filtered images are grayscale and represent complementary colours of primary.

  • Red filtration image represents cyan output
  • Green filtered image stands for magenta
  • Image filtered through blue represents yellow.
  • For neutral tones like shades of grey and black, a special filter called amber is used to get grayscale representing neutral values.

Halftone

Halftone is a process of breaking down the image into a structure of tiny dots of constant tone. Colour filtered images are still in continuous tones & only four inks cannot produce more colours directly. To make this possible, the images undergo a process called halftone which breaks the image into tiny dots of fixed tone. This is binary conversion so that in single impression with one ink varied values can be printed. These varied values are outcome of interplay of whiteness of paper & colour of ink. The density of dots at a place decides tone of that place, Thus a halftone image appears full tone when all four colours make impression on paper

A Halftone representation of Semester Four

Assembly

The treated images & formatted story-blocks of text are assembled together to form a complete page. This is called page make up. Page make up is layout or sometimes a print ready design.

Today in digitization the text input & formatting as well as image editing to some extent is done on same software or different softwares but on same computer. This brought publication process on to single desk. This single desk operation is termed as Desktop Publishing (DTP)

Pagination

Pagination is a process of arranging pages onto a larger printable page order so that after binding the pages fall in numeric sequence ar bigger than the actual page format (size). This helps many pages to be printed in one impression. Taking advantage of this the pages are arranged in such a way that once the printed page is folded the next page falls in consecutive number to make a folder, or a book.

Plate Making

Plate is a master & is prepared in pre-press as end product of the stage in traditional method. In digital method a print ready file is forwarded to press where it is used to prepare a master as per the printing technology to be used


What is Colour Separation?

Color separation is the process by which original full-color digital files are separated into individual color components for four-color process printing. Every element in the file is printed in a combination of four colors: cyan, magenta, yellow, and black, known as CMYK in the world of commercial printing. By combining these four ink colors, a wide spectrum of colors can be produced on the printed page.

In the four-color printing process, each of the four color separations is applied to a separate printing plate and placed on one cylinder of a printing press. As sheets of paper run through the printing press, each plate transfers an image in one of the four colors to the paper. The colors—which are applied as minuscule dots—combine to produce a full-color image.

The actual work of making the color separations is usually handled by the commercial printing company, which uses proprietary software to separate your digital files into the four CMYK colors and to transfer the color-separated information to plates or directly to digital presses. Most print designers work in the CMYK model to more accurately predict the appearance of the colors in the final printed product.

 

Typically color separation is the responsibility of the color separator. This includes cleaning up the file to make it print ready and creating a proof for the prepress approval process. The Process of color separation starts by separating the original artwork into red, green, and blue components (for example by a digital scanner). Before digital imaging was developed, the traditional method of doing this was to photograph the image three times, using a filter for each color. However this is achieved, the desired result is three grayscale images, which represent the red, green, and blue (RGB) components of the original image.

The next step is to invert each of these separations. When a negative image of the red component is produced, the resulting image represents the cyan component of the image. Likewise, negatives are produced of the green and blue components to produce magenta and yellow separations, respectively. This is done because cyan, magenta, and yellow are subtractive primaries which each represent two of the three additive primaries (RGB) after one additive primary has been subtracted from white light.

Cyan, magenta, and yellow are the three basic colors used for color reproduction. When these three colors are variously used in printing, the result should be a reasonable reproduction of the original, but in practice this is not the case. Due to limitations in the inks, the darker colors are dirty and muddied. To resolve this, a black separation is also created, which improves the shadow and contrast of the image. Numerous techniques exist to derive this black separation from the original image; these include grey component replacement, under color removal, and under color addition. This printing technique is referred to as CMYK (the “K” stands for key, a traditional word for the black printing plate).

Today’s digital printing methods do not have the restriction of a single color space that traditional CMYK processes do. Many presses can print from files that were ripped with images using either RGB or CMYK modes. The color reproduction abilities of a particular color space can vary; the process of obtaining accurate colors within a color model is called color matching.


Discuss Halftone and explain LPI.

Good News. We dont have to actually Explain Halftone. Just Discuss and Chill.
Its gonna be like “Hey Baby you believe in Halftone at first print and stuff? Want me to print again?

Halftone

Halftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect. “Halftone” can also be used to refer specifically to the image that is produced by this process.

 

Where continuous tone imagery contains an infinite range of colors or greys, the halftone process reduces visual reproductions to an image that is printed with only one color of ink, in dots of differing size (amplitude modulation) or spacing (frequency modulation). This reproduction relies on a basic optical illusion: the tiny halftone dots are blended into smooth tones by the human eye. At a microscopic level, developed black-and-white photographic film also consists of only two colors, and not an infinite range of continuous tones.

Just as color photography evolved with the addition of filters and film layers, color printing is made possible by repeating the halftone process for each subtractive color—most commonly using what is called the “CMYK color model”. The semi-opaque property of ink allows halftone dots of different colors to create another optical effect—full-color imagery.

The resolution of a halftone screen is measured in lines per inch (lpi). This is the number of lines of dots in one inch, measured parallel with the screen’s angle. Known as the screen ruling, the resolution of a screen is written either with the suffix lpi or a hash mark; for example, “150 lpi” or “150#”.

The higher the pixel resolution of a source file, the greater the detail that can be reproduced. However, such increase also requires a corresponding increase in screen ruling or the output will suffer from posterization. Therefore, file resolution is matched to the output resolution.

Typical Halftone Resolutions

Screen printing                                –                45–65 lpi

Laser printer (300dpi)                        –                65 lpi

Laser printer (600dpi)                        –                85–105 lpi

Offset press (newsprint paper)                 –                85 lpi

Offset press (coated paper)                –                85–185 lpi

LPI

This actually refers to the number of dots-per-inch in a halftone but the term is LPI and not DPI. LPI and DPI can be easily confused. This term is also known as the frequency in computer graphics (frequency of lines-per-inch). The standard LPI of a screen printable design is 35 LPI to 45 LPI for cartoon type work and from 55 lpi for manual   process prints to 65 lpi for automatic process prints. The higher the number the smaller the dot and the harder it is to put on a screen.

Lines per inch (LPI) is a measurement of printing resolution. A line consists of halftones that is built up by physical ink dots made by the printer device to create different tones. Specifically LPI is a measure of how close together the lines in a halftone grid are. The quality of printer device or screen determines how high the LPI will be. High LPI indicates greater detail and sharpness.

Printed magazines and newspapers often use a halftone system. Typical newsprint paper is not very dense, and has relatively high dot gain or color bleeding, so newsprint is usually around 85 LPI. Higher-quality paper, such as that used in commercial magazines, has less dot gain, and can range up to 300 LPI with quality glossy (coated) paper.

In order to effectively utilize the entire range of available LPI in a halftone system, an image selected for printing generally must have 1.5 to 2 times as many samples per inch (SPI). For instance, if the target output device is capable of printing at 100 LPI, an optimal range for a source image would be 150 to 200 SPI. Using fewer SPI than this would not make full use of the printer’s available LPI; using more SPI than this would exceed the capability of the printer, and quality would be effectively lost.

Another device that uses the LPI specification is the graphics tablet.


What is pagination? Draw a diagram of 8 page brochure imposition.

Pagination is the process of dividing a document into discrete pages, either electronic pages or printed pages.

In reference to books produced without a computer, pagination can mean the consecutive page numbering to indicate the proper order of the pages, which was rarely found in documents pre-dating 1500, and only became common practice c. 1550, when it replaced foliation, which numbered only the front sides of folios.

Today printed pages are usually produced by outputting an electronic file to a printing device, such as a desktop printer or a modern printing press. These electronic files may for example be Microsoft Word, PDF or QXD files. They will usually already incorporate the instructions for pagination, among other formatting instructions. Pagination encompasses rules and algorithms for deciding where page breaks will fall, which depend partly on cultural considerations about which content belongs on the same page: for example one may try to avoid widows and orphans. Some systems are more sophisticated than others in this respect. Before the rise of information technology (IT), pagination was a manual process: all pagination was decided by a human. Today, most pagination is performed by machines, although humans often override particular decisions (e.g. by inserting a hard page break).

The operator will also use this sheet to check for pagination, or the order of pages, by folding the parent sheet to final-product size. This process confirms that all the pages will be printed in the proper order and that they will appear right-side up when bound together.

Pagination Process

Pagination is not as simple as 1,2,3. This process has rules and algorithms for deciding where page breaks fall. Although most printers use computer systems to automate pagination, sometimes a press operator will override the computer to manually adjust the pagination as needed.

Page Count Explanation

Find a piece of paper and fold it in half three times. Notice how each time you make a crease, you increase your page count by four? This folded sheet is how your pages will be inserted and bound into your book as a unit. It’s also why page counts must be in multiples of 4.*

Impostition / Pagination

8 Page Brochure Imposition.

This is the one for which the given explanation is all about

Lets take an illustration. Consider we have to print small pocket size pamphlet of eight pages. For a pocket size we have to choose a paper of the size A-6. To get a folder with binding at the left edge we will need four sheets of A-6 Paper. Each paper will hold two pages back to back to make 8 Pages in total.

A-4 paper when folded, once against horizontal divide & then against vertical divide, we get eight sides of A-6 size as shown in the illustration. Look at the diagram for

the page numbers & their order.

Apparently the order is strange & may not make sense how this will provide a required order. But this is the way to arrange pages for printing so that at once eight pages are printed. The printed sheets are called signature. After printing the signatures go ahead for finishing. In finishing the pages are folded as per decided sequence to get the pages in sequence. The binding process takes place according to number of pages and the type of binding required

 In this above example of eight page booklet, the binding will be done with staple at the spine and the folded side is trimmed to open the fold and separate the pages.

This is the basics of pagination. The pagination is necessary step in any publication so that the number of impressions and the time is saved yet the desired output quantity is achieved. The example shown is sixteen page booklet


What is Die cutting? Write application of Die cutting.

Didnt find a lot of applications..

Die-cutting is a process used in many different industries to cut a thin flat material (in our case, paper) into a specific shape using a steel cutting die.  It can be used to punch out a decorative shape or pattern to incorporate within a larger piece, or it can be used to create the main shape of an object by cutting the entire sheet of paper in an distinct/designed way.  More simply put: for us it’s way of making a hole in paper in a desired shape using the same presses that we use for letterpress printing.

In commercial printing, die cutting is a process that cuts slits or shapes out of a completed print project. The die cuts may be utilitarian small straight cut lines to hold an inserted business card or a circle and a slit for hanging a printed piece on a doorknob. A larger die cuts the shape of an entire pocket folder, preparing it for folding and gluing. Die cutting may also be solely decorative or attention-getting, cutting shapes into a print job to make it more attractive or noticeable.

Die cutting is part of the finishing process after a print job has run through the printing press and is ready to be trimmed and finished in whatever manner the piece requires.

A die is a thin razor-sharp steel blade that is shaped, mounted on a base and attached to a press similar to an old-fashioned letterpress. The printed sheets are then run through the press and the die stamps each sheet individually to cut out the desired shape.

Die cuts on a piece can allow the text or part of an image to show through from the inside after it is folded. Die cutting can be used to create rounded corners, flaps, holes, windows or pop-ups. An entire piece may be die cut into a unique shape.

On a page of decorative labels, the die may cut shapes like a circle, rectangle, star or another standard shape in the label stock without piercing the backing—a process known as a kiss cut. Contour die cuts can loosely or closely follow the shape of an image.

Printers usually have standard dies for common cuts. Custom dies can be made, but they substantially increase the cost of the print project and delay the production process. Because all dies consists of metal that must be bent into the shape of the cut, complicated shapes may not work.

Like letterpress, a die-cut element draws attention to the 3D nature of paper and the character of the material itself.  We mostly use die-cutting as a feature – taking an industrial process and turning it into a design element.  As a letterpress print shop, here are some common ways we use die-cutting:

  • to create die-cut windows for messages on greeting cards
  • to create a unique shaped greeting card (examples include heart die-cuts, scallops, mini-paper sculptures)
  • as a design element in one of our new wedding suites
  • to create die-cut coasters, hang tags, and rounded corners on business cards for clients
  • to make the boxes in which our cards are packaged

Explain Silk screen printing process. Discuss the advantages and limitation of it.

Silk-screen printing is one of the most popular printing techniques, and is the most-used by companies when printing designs onto products of different sizes and materials.

Silkscreening is the method used to print designs on anything from T shirts, fabric and even wood. It has been used for more than 100 years in the commercial and artistic sector and is mainly used for printing images and designs on T-shirts, tote bags, paper, wood, ceramics and other materials.

There are different types of silk-screen printing, depending on the aim and the printing process used. Among them, we can find serigraphy for the graphic design sector, serigraphy for the art sector and textile printing, which is what interests us most.

silkscreen printing work?

Silkscreening & Art Stenciling

You may be surprised at how similar the screen printing process is to those stencils you used to draw and color with as a kid. While the process is simple—it did originate more than a 1000 years ago—it can take years of practice to master the art of lining up each ink stencil properly (“registration”) and evenly apply the ink substrate with adequate pressure. The more skilled and experienced you become in silkscreening, the more advanced and intricate your designs will be. Serigraph printing is cheap, but it takes skill and experience, so it’s usually done in a commercial or business setting. If you want to learn how to silk screen print at home, it would probably be a good idea to take an art education course or learn from a master first.

How does it work?

Silk-screen printing

While silkscreening is a type of printing, the silk printing press machine used is not quite like the printer you’re thinking of. As you might guess, screens are key to the silk screen printing method. Much like an art canvas, the screen or mesh is stretched very tightly over a frame. Traditionally screen printing was done with screens made out of silk (hence the name) but today polyester screens are more common since they often cost less.

Screen printing begins with mounting multiple silkscreens over whatever material you want to print your design on, one screen for each color. Once you have the screens or stencils arranged in the design you want, you roll, press, sponge or squeegee your ink over the silkscreen stencils to leave a negative design. When you’re all done, you remove your silkscreens to see your custom design left on the material beneath.

– Excellent quality-price ratio for large print runs

– Perfect colour reproduction

– Durability of personalised items

– Printouts that are resistant to many washing procedures

Silk-screen printing is recommended for designs of up to four spot colours, for example logos, phrases and simple graphic designs. For short runs and more complex printouts such as photographs or designs with gradations, digital printing is recommended. Here is a table for comparing the two techniques and choosing the one that best suits your business:

What kind of ink is used for serigraph printing? In traditional silk screen printing, water based ink or ink made from plastisol type derivatives were most commonly used, each containing special ingredients that would improve the drying and adherence quality when applied. Much of the technical formula had more to do with optimizing each step in the screen printing process, a consideration that was eliminated with today’s modern “inkjet to garment” machines.

For these new rotary silk printing machines, usually dye or pigment based ink is used, depending on the time when the machine was manufactured. Once you choose the type of silkscreening press you want to use, do not interchange the type of ink. The result may resemble “jello” in its worst form. As for options within each ink classification, all of these machines usually rely upon Epson inkjet print heads. Alternative ink choices on the market today are then virtually interchangeable since all have been designed to work with the same technology.

Advantages

  • The Screen Printing is the cheapest among printing technologies in practice
  • It is simplest to use and plate making is fun
  • It prints on any possible surface which can be made or is flat
  • With little modification screen technology can be used to print on cylindrical materials such as pens and pipes by creating the stencil on the surface of a tube or making a provision for rotary movement of the cylindrical substrate.
  • Easiest for small jobs, short runs, prints wedding and invitation cards as well as visiting cards. Cards are small in quantity and size, so a mass printing technology would not be feasible
  • Gives freedom of any combination of colours and doesn’t rely on CMYK Module, eliminating the colour separation stage.
  • Simple opaque design, cut on paper can also be used to make plate without the need of negative-positive film expenses
  • Screen printing is a method that can accommodate a wide range of different materials. This means printers can produce T Shirts, promotional banners, hats and even posters from same screens. Same plate can be used to print on the varied surfaces without the need of different plates for different surfaces.
  • Can change inks or colours midway to get variety especially in fabric printing
  • The printing run can be stopped at any time and resumes without loss of material and wastage of paper

Disadvantages

  • The method is not suitable for quantity job. It is too slow to meet deadlines
  • Photographic quality is not possible because screen pores are larger than a halftone screen, so resolution is less
  • Precise registration is difficult to achieve through job because paper replacing and aligning to easel is manual and causes errors when more than one colour is used to build one image. The impression appears shifted.
  • The inks are pushed through the mesh so difficult to get exact tones out of mixing of the inks. But prepares mixed inks can be used to maintain the colour accuracy
  • Though screen printing needs less prior preparation the steps during actual printing of multi colour job are more and tedious
  • Small problems during the printing of any single screen could create an issue, that offsets or distorts the completed image
  • The limitations of screens as well as the techniques used to apply the ink to the fabric make it difficult to create small and intricate details
  • The exact limitations vary depending on the printer and the equipment. Attempting to print designs with small details can sometimes result in technical problems, color bleeding and poor print quality

Though disadvantages outnumber advantages, biggest advantage is that the technique is a low budget cost, it might be slow but gives freedom of printing anywhere and any [flat] surface]


Explain gathering, collaring and saddle stitching.

Books, Magazines, and newspapers come under reading material and all the reading material have a certain specified page sequence. The material is spread over several pages and the page order must be maintained as it is designed for. The is maintained throughout since pagination in prepress to press while loading paper of appropriate width so that several pages are pruned in one go. Yet there is minimal wastage in trimming. A Pruntin cylinder can print at a length of pper equal to its circumference and can accomodate number of pages the length as well as the width of the cylinder can print. This is why several signatures must be brought together to compile the printed signatures into a proper book.

The signatures are folded into forms of finite number of pages. These forms are combined together to make a full length book. There are three ways of doing so. According to the total number of pages of the book or magazine, one way is preferred over the other and accordingly the binding method to changes. But this has to be taken in account while paginating in pre-press or while mounting plates in press stage. There are three ways of bringing the pages together as well as to bind.

  • Collating leads to Saddle Stitch
  • Gathering Leads to Staple Bing
  • Perfect Binding

Collating and gathering are processes in finishing stage. Signatures once folded are bound into a book or magazine. Magazines and books are several pages long and so many pages are not printed at once due to limitations of physical size and changing matter.

This is why a printable size of paper accommodates sixteen or eight pages back to back. This makes one form. The content on next sixteen pages is printed on another signature. This also makes one more form. The two forms have to be bound so that we get thirty two pages.

If you have a glance at the form you will notice that the second form can be places inside the first or places next to the first. The page number will differ in both cases.

Collate

In printing, the term Collate refers to the gathering and arranging of individual sheets or other printed components into a predetermined sequence. Basically, Collating creates consistent, logical sets from multiple parts. Diagram A illustrates four sets of documents which have been collated. Diagram B illustrates four sets of documents which have not been collated.

Bear in mind that the individual parts of a print project can be collated without having to be bound or fastened together. For example, promotional packets – like those used for seminars, sales presentations, trade shows and other marketing purposes – are often collated in advance for easy distribution. Likewise, printed instructional handouts may be collated in a particular order but are not necessarily bound or fastened together.

Gathering

In bookbinding, a section, gathering, or signature refers to a group of sheets, folded in the middle, and bound into the binding together. Gathering machines have up to thirty slots or pockets in which signatures are fed manually or automatically. The machine then gathers the signatures into what is known as a book block. Such machines can also have a binding function, such as for instance a stitcher.

The section is the basic building block of codex bindings. In Western bookbinding, sections are sewn through their folds, with the sewing thread linking each section to its neighboring sections.

The gatherings can be seen by looking at the top or bottom sides of the book, though cheaper modern books are perfect bound with no gatherings, gluing each sheet directly to the binding. The gatherings are sewn into the binding and the middle sheet of each gathering will have two or more short stretches of thread visible at the central fold.

In medieval manuscripts a gathering, or quire, was most often formed of 4 folded sheets of vellum or parchment, i.e. 8 leaves, 16 sides. The term “quaternion” (or sometimes quaternum) designates such a unit. A gathering made of a single folded sheet (i.e. 2 leaves, 4 sides) is a “bifolium” (plural “bifolia”); a “binion” is a quire of two sheets (i.e. 4 leaves, 8 sides); and a “quinion” is five sheets (10 leaves, 20 sides). This last meaning is preserved in the modern Italian meaning of quire, quinterno di carta. Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the number of sheets and pages in a gathering became more variable.

Saddle Stitching

The method of placing forms collateral to each other is called collating, Collated forms don’t share common spine and hence the individual forms need to be stitched t a common strip called saddle. One the forms are tightly stitched to the common saddle the saddle is pasted to binding cover. The binding cover is mostly a pair of hard bound board and binding cloth strip that holds these boards, saddle and pages together

In the printing industry, Saddle Stitching refers to a very popular book binding method in which folded sheets are gathered together one inside the other and then stapled through the fold line with wire staples.  The staples pass through the folded crease from the outside and are clinched between the centermost pages.  Two staples are commonly used but larger books may require more staples along the spine.

Saddle Stitching may sound like an odd name for a book binding process that places wire staples through sheets of paper but in the printing industry stapling is commonly called Stitching. Also, the collated sheets are draped over a Saddle-like apparatus during the stapling/stitching process, hence the name Saddle Stitching.

In diaries, and reference books or books with more than 80 pages this kind of binding is adapted. This is called saddle stitching. It is a lengthy process and a costly one too.


What are the various factors consider in print production?

Now. There is no definite Answer. So You Know What to Do

It is very crucial to understand how detailed and complex the print process truly is, and the value of working with someone who has the expertise to ensure your job is handled correctly. There is an enormous difference between a quality print job and simply sending your files to a local franchise print shop.

1) Binding Style

Magazines are typically bound with the Saddle-Stitch method or the Perfect Binding method. In most cases, the binding style you choose will be dictated by the number of pages in your magazine.

If the page count is relatively low, the Saddle-Stitch method is recommended. Saddle-stitched magazines are constructed from folded sheets that are held together by wire staples. The staples are driven through the crease of the magazine’s spine to secure the pages as a unit. Though simple, the result is a very professional looking magazine.

In addition, saddle-stitching is a very economical binding option. It also allows the magazine to lie almost flat when opened. This works well for artwork that spans two adjacent pages (also known as crossover images).

Conversely, if your magazine has a relatively high page count, the Perfect Binding method is recommended.  Perfect Bound magazines are created by gluing the pages and cover together at the spine with a strong, flexible glue. The other three sides of the magazine are then trimmed as needed to give them clean “perfect” edges. Also, unlike the saddle-stitch method, perfect binding often allows for printing on the magazine’s spine.

 2) Dimensions

The dimensions refer to the width and height of the magazine in its finished form (also known as the trim size). Although magazines can be printed with just about any size you choose, bear in mind that all commercial printers have certain page sizes they offer as standard sizes.

These standard sizes are determined by the type of production equipment used by the printer. Designing your magazine’s page size to conform to one of your printer’s standard page sizes will optimize the production of your magazine and keep the cost as low as possible.

On the other hand, a magazine designed with non-standard page dimensions may not match well with any of your printer’s presses. As a result, the production run would be inefficient and have a poor paper yield. The excess paper becomes waste and can add quite substantially to the cost of a magazine run.

Needless to say, knowing which page sizes your printer can produce most economically is good information to have before starting on the layout of your magazine. Not to discourage creativity or unique design, but a few subtle design changes upfront could translate to big savings later. So get your printer involved early in the process.

Furthermore, a magazine’s size not only affects its production cost, it can also affect the postage cost to distribute the magazine to readers. So, if your magazines will be sent individually through the mail, your printer will likely be able to make size suggestions to help keep your mailing costs as low as possible. Sometimes tweaking your page dimensions by as little as 1/2” can result in a postage decrease.

3) Quantity

The quantity of magazines being created in a single production run will determine the type of printing press best suited for producing it. Because most established magazine titles have high readership levels and widespread distribution, the run quantities are large enough to warrant production on high-speed web presses.

A web press is an offset printing press that is fed from huge rolls of paper. As the paper unwinds from the roll, it forms a continuous “web” through the press. This web of paper is held taught by a series of rollers, which move the paper through the press. The paper is cut into smaller parts after receiving the inked images. A web press is the most cost-effective printing method for large runs of magazines and other multi-page documents.

However, a start-up magazine will not likely have a large production run…at least in the early going. Hence, initial runs of a recently-launched magazine are more likely to be produced on a sheet-fed printing press. Unlike a web press, which is fed from a continuous spool of paper, a sheet-fed press has separate sheets of paper entering the press one after another.

Web presses and sheet-fed presses both create high quality printing, but magazines produced on a web press will have a lower unit cost than magazines produced on a sheet-fed press. But again, the production volume must be large enough to necessitate a web press run…a volume level that a new magazine title may take a while to achieve.

Also, just because the unit cost of a magazine decreases as the order quantity increases, it is still wise to consider which run size is optimal for your specific situation. A lower unit cost is great, but not if you’re ordering more magazines than you’ll ultimately need.

4) Page Count

In addition to determining the binding style, the page count of your magazine (along with the total quantity of magazines needed) will help your printer calculate how much paper is needed to produce your project.

When you relay the magazine’s page count to your printer, be careful. Page counts are often miscommunicated. For example, open up a magazine and flip through it. As the individual sheets flip by, notice that each of these sheets has two sides. Your printer refers to each side of these sheets as a separate page. So to a printer, every sheet within the magazine represents two pages. However, those new to printing often refer to each sheet within the magazine as one page.

5) Ink Colors

Many magazines are produced with a full-color cover and full-color pages. This is because full-color provides maximum visual impact. This is especially true if your magazine accepts advertisements. Often, there is a mixture of full-color images and black-ink text.

Should one assume that money will be saved by using more black-ink pages than full-color pages? Well, sometimes yes and sometimes no. It really depends on the layout of the magazine, and where the black-ink pages fall in relationship to the color pages.

Also, your printer may ask if any ink coverage extends all the way to the edge of the pages or cover (known as a Bleed). If so, the artwork layout will need to be created slightly larger than the finished trim size. Crop marks will also need to be added, so your printer will know exactly where to trim off the sections that bleed. If in doubt, check with your printer before getting too far along in the design phase.

6) Paper Characteristics

Most magazines use a very thin paper stock for the interior pages. One reason for the light stock is that magazines do not normally see frequent use. In most cases, a magazine is generally only looked through a few times. This means long-term durability is not really a factor in the construction of the magazine.

Another reason for using light stock is that many magazines are distributed through the mail. A lighter paper stock means less weight, which can reduce postage costs. A third reason is that thinner paper helps reduce bulkiness, which can become an issue if the page count of the magazine is on the high side. A fourth reason is that thinner paper is cheaper than thicker paper.

We mentioned the use of web presses in point #3 above. A web press can print on very light paper stock. However, a sheet-fed press encounters problems when printing on very lightweight stock. This means a newly launched magazine may have to start off using thicker paper for its pages because the production volume may initially be too low for a web press. But as the magazine gains readership, production can then switch from a sheet-fed press to a web press in order to capitalize on the efficiencies associated with a web press. Namely, a higher running speed, improved paper yield, and the ability to print on thinner (and less expensive) paper stocks.

In addition to paper thickness, the paper characteristics you select – such as texture and sheen level – largely depend on the image you are aiming to project.  For example, a magazine made with a heavier, lustrous cover provides a higher image of quality than a thinner, duller cover.

There are also a variety of paper coatings available to enhance the look and durability of your magazine. For example, you may wish to have a clear coating – such as a gloss aqueous coating or a high-gloss UV – applied to the cover of your magazine. A high-gloss UV coating not only increases the durability, it also enhances the vibrancy of the ink colors and makes your cover artwork grab attention.


Draw a diagram of Lithographic Offset printing and name its parts. Explain in brief.

Offset printing, also called offset lithography, is a method of mass-production printing in which the images on metal plates are transferred (offset) to rubber blankets or rollers and then to the print media. The print media, usually paper, does not come into direct contact with the metal plates. This prolongs the life of the plates. In addition, the flexible rubber conforms readily to the print media surface, allowing the process to be used effectively on rough-surfaced media such as canvas, cloth or wood.

The main advantage of offset printing is its high and consistent image quality. The process can be used for small, medium or high-volume jobs. There are two types of offset printing machines in common use for publication today. In sheet-fed offset printing, individual pages of paper are fed into the machine. The pages can be pre-cut to the final publication size or trimmed after printing.

In web offset printing , larger, higher-speed machines are used. These are fed with large rolls of paper and the individual pages are separated and trimmed afterwards. Sheet-fed offset printing is popular for small and medium-sized fixed jobs such as limited-edition books. Web offset printing is more cost-effective for high-volume publications whose content changes often, such as metropolitan newspapers.

Anatomy of an offset printing press

A sheetfed offset press consist of the following components:

The sheet control system

  • This mechanism transfers the sheets of paper that will be printed on through the press.
  • In the feeder section sheets are picked up from a paper pile. The stack of sheets is placed on an adjustable pile table. Jets of air and/or a vacuum make sure the feeder mechanism only picks up a single sheet of paper each time. That sheet is then transferred to a feedboard where it is properly positioned before being transferred to the printing unit.
  • In the infeed section each sheet of paper is transferred to grippers on the impression cylinder.
  • If the press has multiple printing units, the transfer section assures that the sheet moves to the next impression cylinder. This is typically done using some kind of chain mechanism.
  • Once the printed sheet leaves the final impression cylinder, the delivery section carries the sheet to the delivery pile. This is a table on which the printed sheets pile up in a stack.

One or more printing units

A printing unit contains everything needed to print one color on the sheet of paper that is moved around by the sheet control system. Offset presses typically contain 1 to 10 printing units.

A single-color press contains one single unit to transfer ink to one side of the printing sheet. To print on the other side you have to wait until the ink has dried, then rotate the pile of paper 180 degrees and print on the other side.

A press with 4 printing units can print full-color text and images using cyan, magenta, yellow and black ink. Often a fifth printing unit is added for varnish or maybe adding a special metallic ink or so. Such a press with 5 units still only prints on one side of the paper.

By adding a reversing cylinder and another 5 printing units, you end up with a very long and expensive press with 10 printing units that can print up to 5 colors on both sides of the press sheet. Such a press that prints on both sides of the sheet simultaneously is called a convertible perfector press.

A printing unit consists of the following components:

The inking system

The ink fountain is a reservoir that holds ink. Offset ink is not a fluid ink, it looks more like a kind of thick paste. From the ink fountain, this ink needs to be transferred to the printing plate or cylinder. From there that ink will be transferred to the paper or another substrate.

The inking system is responsible for this transfer. It needs to break the thick, viscous ink down into a thinner, more workable and uniform ink film. This is done using a set of rollers. Presses can have up to 10 (or even more) rollers in their roller train. The amount of ink is usually controlled by so-called fountain keys that control the gap between the ink fountain and the first roller. The wider open this gap is, the more ink can be picked up by the roller. Controlling that gap is done manually with a screw on some presses but nowadays those keys are often motorized.

The fountain keys are lined up in a series across the width of the ink fountain so that more ink can be transferred to the left part of a page if there are more images or solid tints on that side of the paper. Some presses do not use fountain keys: they periodically dip the first ductor roll in the ink fountain and control the amount of ink that is picked up by the duration of that dip. The inking system assures that a thin layer of ink that is typically 0.2 to 0.4 mils thick is transferred to the printing plate.

The dampening system

The dampening system makes sure the non-image areas of the printing plate are moistened so that they will repel ink. This is mainly done using water, but additives are needed for long print runs to improve the ink repellency, lower the surface tension, desensitize the non-image plate regions and make sure corrosion, mildew, bacteria, and fungi don’t cause issues. That’s why gum, alcohol, a fungicide, and other agents are added to the water of the fountain solution.

To make sure an even layer of water is put down on the non-printing parts of the printing plate, a mechanism similar to the inking system is used. The dampening system is, however, less complicated and requires fewer rollers.

The plate, blanket and impression cylinders

The plate cylinder is a large roll to which the printing plate is attached. The plate is usually made of aluminum. Its non-imaging parts will be covered by a thin layer of water that is applied by the dampening system. This means the ink which is fed by the inking system will only adhese on all the other areas.

During printing this image created by ink is transferred to a rubber blanket that is attached to the blanket cylinder. From there is the image is transferred to the press sheet.  An impression cylinder carries the paper through the printing unit and provides a hard backing against which the blanket can impress the image on the paper.

Not all presses use impression cylinders: there are for example perfecting presses that print blanket-to-blanket: the impression cylinder is replaced by a second blanket cylinder, printing both sides of the press sheet simultaneously in a single printing unit.

A Quick Two Minute Video About the Process

Click Me. Please. I beg. Dont be racist because I am blue COME ON!


Write four advantages and four disadvantages of Offset process.

The offset printing press uses spinning cylinders rather than an up-and-down motion to create prints quickly and efficiently. Think of the cylinders like a cross between a gear and rolling pin. They touch one another, spinning quickly and smoothly, propelling each other around. {brb. I think-ed too intensly} The ink transfers from one cylinder to the next, going through refining along the way, until it is printed on the paper. Paper is fed either in large size sheets like in a sheetfed printing press, or in a large continuous spool like in a web fed press.

Offset presses are also faster because they can process more colors, which mix throughout the printing process. For example, some Komori offset printers come equipped with four of six colours processing, allowing you to diversify how many different colors you can effectively create on the page

Advantages of Offset Press

  • The use of rubber blanket facilitates printing on less expensive paper and also allows perfect transfer of ink onto paper
  • The process is fast and can print large number of copies
  • Offset can print on large size of paper and also print on other material such as tin, plastic, aluminium foil, etc.
  • Amount and thickness of ink can be controlled and undue wastage of ink can be saved
  • Master plate surface is prepared at very fast speed using computers, photographic, electronic and mechanical techniques which go well with modern reproduction methods.
  • Good quality pictures, multi-colours can be easily printed.
  • Four identical printing machines make a set of four colour printing and are perfectly synchronized to create precise registration from impression to impression to produce exact colours and sharp images.

Disadvantages of Offset Press

  • Skilled personnel required to operate the machine
  • For last minute changes or corrections the whole plate has to be prepared again
  • Machine maintenance of an offset machine is expensive because it has large number of moving parts. High speed operation causes high wear and tear
  • More space is required to set up the machine
  • To set the job a lot of initial time is taken
  • Wastage can be higher as a lot of paper runs till the mistake is noticed
  • Initial investment is more. Power consumption is high overhead

Compare between offset and gravure printing process.

Gravure Printing

In gravure printing, the image is applied to a printing substrate by use of a metal plate mounted on a cylinder.  It uses a depressed or sunken surface for desired image.  The image to be reproduced is etched into the metal plate, sometimes using a laser.  The metal plate is bathed in ink then wiped clean before application.Bottom line:

  • Gravure printing produces high quality results rapidly but costs are significantly higher than using other printing methods.

Offset Printing

Inked image is transferred (offset) from a plate to a rubber blanket, then to printing surface.

  • Inferior image quality
  • Propensity for anodized aluminum printing plates to become sensitive (due to chemical oxidization) and print in non-image/background areas when developed plates are not properly cared for.
  • Large quantity of time and high cost associated with producing plates and printing press setup.

So here it is, a quick look at the key feature, process and benefit differences of Gravure and Web Offset printing:

  • The gravure printing process has the ability to print a smoother image and more consistently on lightweight papers.
  • Web offset printing presses have fixed cylinder cutoffs, whereas gravure presses have a variable cutoff dictated by the cylinder diameter used.
  • Web offset dots are printed as a round dot; gravure ones are hexagonal.
  • Web offset uses a printing plate; gravure a cylinder engraved with cells which carry ink.
  • Web offset is an offset printing process, whereas gravure is intaglio (i.e. the cylinder comes into direct contact with the paper and is not offset).
  • Web offset inks are dried by heat from a gas oven. Gravure inks contain a solvent called Toluene which, as well as being toxic, evaporates, hence drying the ink without heat.
  • Web offset presses can print either long or short grain; gravure prints short grain, due to folder configurations.
  • Web offset printing is suitable for 8pp A4 sections upwards from runs of 50,000 upwards. Normally gravure will print sections from 8pp to 168pp in size and is competitive for runs, usually, from several hundred thousand to millions of copies.
  • Web offset plates will run for around a million impressions; gravure cylinders, which are coated in chrome, can last for over 20 million impressions.
  • The set-up costs of a gravure press are several times that of a Web offset printing press – hence the size of run needed for the process to be competitive.

Here is  Super Slow and Strong Look at both Methods/Technologies

Press planning and paper consumption

In offset printing, the plate does not come into contact with the paper. Instead, it transfers the image onto an intermediate rubber blanket that contacts the paper and prints the image. Offsetting the image onto the blanket allows for a more complete transfer of the ink onto the rough paper surface. Two common offset presses are Harris-Heidelberg’s M1000, which prints 32 standard-size pages at a time, and M3000, which prints 48 standard-size pages. Paper rolls for offset presses can’t exceed 56″.

The page height is determined by the fixed cutoff, or circumference, of the press cylinder. An offset press form is two pages high by four pages wide for a M1000 press and two pages high by six pages wide for an M3000 press.

Because the cutoff size is fixed, you waste paper if the head-to-foot size is inefficient. For instance, if your book is 9-3/4″ tall on a 10-1/2″ cut-off press, you throw away a strip of paper 3/4″ wide for every page printed. But the width of the book can vary without a paper penalty because the roll width is not fixed.

The offset press is usually made up of at least four ink units, which print both sides of the paper web simultaneously. Unlike with the gravure press, ink colors are printed without any drying units between the inking units, so the ink is still wet when the next color is applied. The web goes through a gas-fired oven that dries the ink. Chilled drum rollers then cool the paper before the web is folded into signatures.

During the rotogravure process, the images are printed directly onto the paper rather than via a blanket. The impression cylinder is partially submerged in the ink, with excess ink removed by a thin metal edge called a doctor blade. The cylinder then makes contact with the web of paper, and an electric charge helps transfer the ink from the engraved wells in the cylinder onto the paper. After each color is printed, the paper web goes through a drying unit and is then turned; the colors are printed on the reverse side.

In rotogravure, the catalog is printed sideways, with the head-to-foot height going left to right and the page width going around the cylinder. The gravure press has about 16 cylinder circumferences that allow for different cutoff sizes. The book’s height determines the paper roll width; its width determines the cylinder circumference.

A gravure press can take a 96″ or even a 108″ paper roll, allowing for more pages to be printed per impression than a gravure press. While the offset M3000 prints 48 standard-size pages at a time, a gravure press can print up to 108 pages. And because gravure presses can accommodate both height and width variations due to the number of cylinder circumferences available, they are more efficient in paper consumption.

Print quality

Gravure color is generally deeper and richer than offset, in part because you can apply more ink to an area than with offset. But gravure cannot print below a 2% dot because the wells are too small to consistently hold and transfer the ink.

One downside to gravure printing is the reproduction of fine-line work or small lettering. The diamond shape of gravure dots does not handle small lettering, creating a jagged type, while offset’s round dot structure handles fine lines well. Serif type with thin edges can appear rough with gravure and smooth with offset, but technology is reducing the jaggedness of the type in the former.

Compromises are a matter of fact with offset. Ink color is applied in the direction the web is running through the press, so images that run in line with one another are forced to share color manipulations. Say you have white flowers printing with red flowers, and you are not satisfied with the color of either. If you take red out of the image of the white flowers, you hurt the image of the red flowers; if you put red in the red flowers, you hurt the white ones. You may need to compromise the color of one image for the sake of the other or both because offset color moves on press are not image-specific.

The greater the ink density, the more ink is put on the page. The maximum density of offset ink is about 260% for the four colors — cyan, magenta, yellow, and black — combined, while gravure can theoretically have a maximum density of 400%. Put another way, each color on an offset press averages 65% density, compared with a possible 100% for gravure.

Gravure allows for more precise registration of inks on press than offset because of the rigidity of the printing surfaces. The hard surfaces of gravure cylinders lay down ink in exact spots; there is no flex to control, as the cylinders do not “give.” And gravure inks are drier and therefore more solid than offset inks when applied to the paper. Adding water with offset printing — a frequent necessity — contributes moisture to the paper that, in turn, causes it to swell and change size. In this way, aligning ink colors is more challenging with offset printing than with gravure.

With gravure, the wells for each color are etched in the cylinder with elongated or condensed shapes. Because the wells are interpretations of the halftone dot pattern of the digital files, the chance of a moiré is reduced.

A moiré — a wavy pattern that appears in the dots making up an image — cannot be fixed without stopping the presses. The root of the problem is in the customer’s page files, so the printer will not bear the cost of the downtime. If the moiré is minor you may want to keep the presses running while the prepress house fixes the problem and the printer makes new plates. If the pattern is unsightly, though, you will need to stop the press and wait for new plates.

If the moiré does make it to the plate, the printer’s prepress department can sometimes reburn the plates at a slightly altered angle. The conventional 3M Matchprint and the digital Kodak Approval both have a dot pattern that will show the moiré as it will appear on the press. The stochastic Iris, however, will not show these patterns.

Costs

The cost benefit of using offset vs. gravure is often a matter of page counts and printing impressions. Generally speaking, the more pages you can produce with fewer impressions (turns of the cylinder), the cheaper your printing costs will be. Because offset presses produce fewer pages per impression than a gravure press, gravure should typically be less expensive. But other factors come into play as well.

Cost analysis will show that the point at which offset becomes less cost-efficient and gravure more economical for catalogs 48 pages and smaller is around 1.25 million-1.5 million catalogs, with qualifications such as page size, number of versions, and if the book uses the same paper throughout or a better grade of paper stock for the cover or outer wrap. For books with 52-76 pages, the cost-efficiency of gravure is more apparent, with breakeven of roughly 750,000-1 million impressions. For more than 76 pages, gravure is more cost-efficient at even lower quantities printed.

On a gravure press, a higher page-count book can be printed in one press run with one press make-ready, while offset would require the book to be printed as a number of press forms with multiple make-readies and press runs. For example, a 96-page book would require two M3000 48-page offset press forms, delivering four 24-page signatures. A gravure press run would require one press form and would deliver 96 pages as three 32-page signatures or two 48-page signatures.

PROS

CONS

Can print more pages per impression

Cost-prohibitive for smaller quantities

Provides deeper, richer colors

Cannot print below a 2% dot

Greater color gamut

Poor reproduction of small point sizes, fine-line work

Color corrections can be isolated to one image

Cost of engraving and changing cylinders is high ($10,000-$15,000), making versioning expensive

Precision registration of inks achieved quicker

Color changes possible only across whole width of web

Requires less paper tension

Few closed-loop color-matching systems available

Can run a lighter/cheaper paper

Fewer vendors to choose from, although more are expected to come to the market soon

Averages fewer breaks than offset

If you factor versioning into the cost equation, however, you’ll find that using gravure for smaller quantities (fewer than 1 million-2 million impressions) is prohibitive because the cost of engraving and changing cylinders is relatively high — between $10,000 and $15,000. The press make-ready and cylinder versioning costs could be higher than the actual running charge

.

Conversely, offset plate costs are minor — from $1,500 to $2,500 — when amortized across the complete press run, allowing you to make the most of versioning for different list segments. You could modify the black headline at the top of the page to welcome new customers, switch covers, change prices, or whatnot.

The offset plates are usually aluminum or similar water-friendly metals that are treated with a light-sensitive chemical that attracts oil, When exposed to light with the film overlay or the computer-to-plate (CTP) process and then developed, the image areas attract ink (which is an oil), and the non-printing area repels ink and attracts water.

The process is fairly quick, with less than a half-hour of actual exposure, developing, and baking of the plates. The inexpensive plates and the relative speed of processing make the offset printing make-ready more attractive for short and mid-size runs. But because the plates need replacing after about 1 million-2 million impressions, offset printing requires additional plates for longer runs.

PROS

CONS

Cheaper for smaller books and print runs

Fixed cutoff size can waste paper

Plates are cheap and easy to make, which allows for versioning

Larger books must be printed as a number of forms

Handles fine line work and thin edges well

Greater risk of moirés

Plates can be changed in two hours

Maximum density of ink is only 260%

Several offset vendors using cutting-edge closed-loop color-matching systems

Aligning ink colors is challenging; more tradeoffs required to match colors

More vendors with high-speed, large-format offset presses from which to choose

More tension means you must print on heavier paper stock

Requires additional plates for longer runs

The speed with which offset plates can be changed results in less than two hours press downtime. This can also be an advantage when a color move cannot be made by manipulating the ink fountain but instead requires adjustment to the digital file and new plates made. Gravure cylinder engraving takes hours per cylinder, and four-color changes can take all day.

Other miscellaneous benefits

The paper web tension required for gravure is about 1 lb. per square inch, while offset requires 4.5 lbs. per square inch. With less tension, gravure presses can run a lighter — and less expensive — paper. Gravure can print on coated supercalendered paper that is lighter than 28 lb. Offset, on the other hand, is usually limited to printing on 34-lb. to 38-lb. stock.

Less paper tension also means that the paper web will not break as often. The gravure press averages fewer web breaks than an offset press. This added offset downtime increases the cost and decreases the efficiency.

With gravure, you may have fewer signatures to bind. As we mentioned earlier, the gravure press form will produce more pages for each form than the offset press: With an M3000 48-page press, you will have two 24-page signatures; a gravure press can produce up to 108 pages as three 36-page signatures. More pages per signature translates to fewer pages to bind.

For example, you can produce a 76-page catalog on offset as three 24-page forms and a four-page cover. In gravure it can be produced as two 36-page froms with a four-page cover. Beside the printing savings, this could eliminate one pocket in the bindery, saving about $1/M-$1.20/M catalogs printed.

But the key benefit belongs to offset: more vendors from which to choose. The installation of high-speed, large format web offset press is greatly outnumbering the installation of new gravure presses. In the U.S., many commercial printers have both high-speed 32- or 48-page presses, but only three also have gravure: RR Donnelley & Sons Co., Quebecor World, and Quad/Graphics.

In the end, the differences between gravure and offset are becoming less marked. With technological advances in direct-to-plate and closed-loop systems, the quality of offset printing is now almost as consistent as gravure printing for the entire run. On the gravure side, the electrical assist has improved the quality of fine-line work. The prices of both plates and cylinders are going down, making gravure more competitive in short runs and offset more cost-efficient in long runs.


Discuss in line and off line finishing process in Post press.

Print finishing can be built into a production workflow in three ways:  Off-line, near-line and in-line.

Off-line finishing is when the finishing device is completely separate from the press and there is no communication between equipment.  This makes it is particularly suited to fast and longer print runs on a variety of paper sizes.  With off-line finishing however, every step in the set-up process is manual which requires greater skill as well as time.  But there are benefits. Off-line devices offer the versatility to accept work from multiple print engines whether they are lithographic or digital, deliver at very high speeds and if there is a problem with the print engine, finishing will remain unaffected.  

In contrast to the off-line approach, in-line finishing solutions are linked directly to the print engine.  Set up requires little if no manual intervention, and the fully integrated print and finishing process offers optimal workflow efficiency in which all aspects of the process are streamlined and automated.   The reduction of skilled operator intervention not only delivers labour savings, there is also less chance of human error in set up, resulting in reduced downtime. This makes in-line workflows particularly suited to variable print such as book production, and personalised mailings where integrity of the personal data is vital. Transactional print, for example customer billing, whereby customer vouchers, and personalised letters can be printed and finished in booklet format and enclosed in addressed envelopes all in one single pass.

The short-run nature of digital presses means the finishing process must be carefully analyzed. So let’s look at the in-line and off-line options, and the arguments for each. First, the terms “offline” and “nearline” are commonly confused. “Off-line” has been used to mean that the starting point of the product is a printed sheet, while “near-line” means that you are starting from a printed roll.

There are advantages (and disadvantages) to each approach:

Offline and Nearline:

  • Flexibility: No doubt about this. Decoupling a finishing system from the digital press allows the press to PRINT with no possibility of a stoppage from a downstream device. Stoppages are not trivial on an in-line system. When behind a digital press, a restart of the finisher with the press can take several minutes.
  • When to choose: If your work is mainly short-run AND requires several format/size changes during a shift, then off-line/near-line is the way to go. Keeping a digital press waiting for the finishing system to be made ready is a very poor use of time. Also, if you have to process the work of several different presses, this is the way to go. Last of all, off- or near-line permit good options for future finishing capacity and capability.

In-line:

  • Labor: Most off- and near-line advocates ignore a very crucial component. It takes more people to finish the product this way. And labor is a huge portion of the economics of print today. Having an off- or near-line finishing solution means you need a separate crew to run it. Contrast this with an in-line finishing system that can run with ONE person for both the press and finishing (yes, I have seen this in production).
  • Movement: Many people seriously underestimate this piece of the puzzle. How do you get the work from press-to-finishing? What if the binders are some distance away. Off- and near-line require both moving and staging the work from press to finishing, and often that’s a lot of paper to move around.
  • Integrity: I had a discussion with a customer a while back over why he chose an in-line system over near-line (over the objections of his printer vendor.) His was a high-security booklet operation and he explained that the fewest amount of touches to the work allowed him to sleep better at night.When printed sheets are moved to different devices, things can get out-of-order. Integrity is much better with a printed roll, but an in-line process can produce better tracking and potential recovery of damaged product.
  • When to choose: If the press is running a fixed format size, or size changes are minimal, or if the number of “touches” must be minimized, then serious consideration must be given to the in-line route.

However, when planning an in-line system, make sure you consult with someone who has the experience and knowledge to gauge the “fit” of the various components that will be needed. Questions of speed, paper hand-off between systems, and the operating interface between the modules must all be calculated.


Describe letterpress (Relief) printing with their applications.

The general form of letterpress printing with a platen press, showing the relationship between the forme (the type), the pressure, the ink, and the paper

Letterpress printing, also called Relief Printing, or Typographic Printing, in commercial printing, process by which many copies of an image are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. Letterpress is the oldest of the traditional printing techniques and remained the only important one from the time of Gutenberg, about 1450, until the development of lithography late in the 18th century and, especially, offset lithography early in the 20th.

Letterpress printing is a technique of relief printing using a printing press, a process by which many copies are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. A worker composes and locks movable type into the “bed” or “chase” of a press, inks it, and presses paper against it to transfer the ink from the type which creates an impression on the paper.

In practice, letterpress also includes other forms of relief printing with printing presses, such as wood engravings, photo-etched zinc “cuts” (plates), and linoleum blocks, which can be used alongside metal type, or wood type, in a single operation, as well as stereotypes and electrotypes of type and blocks. With certain letterpress units it is also possible to join movable type with slugs cast using hot metal typesetting. In theory, anything that is “type high” or .918 inches can be printed using letterpress.

Letterpress printing was the normal form of printing text from its invention by Johannes Gutenberg in the mid-15th century until the 19th century and remained in wide use for books and other uses until the second half of the 20th century. Letterpress printing remained the primary way to print and distribute information until the 20th century, when offset printing was developed, which largely supplanted its role in printing books and newspapers. All forms of data collection were affected by the invention of letterpress printing, as were many careers such as teachers, preachers, physicians and surgeons and artist-engineers. More recently, letterpress printing has seen a revival in an artisanal form.


Describe the various stages in Finishing Process [Post Press]

if anything is missed out. Let me know

Finishing refers to all the activities that are performed on printed material after printing. This includes binding, the fastening of individual sheets together, and decorative processes such as die-stamping, embossing or laminating.

Finishing can be:

  • an in-line process – which means that units attached to the end of the printing press perform the finishing operations. This is typically the case with web presses as well as many digital presses.
  • an off-line process – which means that printing and finishing are completely separate processes.

The overview below list major finishing processes.

Bindery processes

Cutting and trimming

Paper stock may need to be cut or trimmed more than once during the production of a job:

  • Sometimes the paper that is in stock is too big and needs to be trimmed prior to printing a job.
  • When multiple signatures are combined on one press sheet, those sheets need to be cut after printing.
  • Sheets may need to be trimmed to fit folding machines or other bindery equipment.
  • After folding and binding the unbound sides need to be trimmed. For books, this is often done with a three-knife cutter, which has three blades to simultaneously trim three sides.

Cutting and trimming are usually done using a guillotine cutter. A stack of sheets is placed on the bed of the cutter and the angled stainless steel blade cuts through it at the desired position. All the stacks are subsequently often placed in a jogger, a vibrating table that squares the stacks of sheets.

Folding

For magazines, books,… large press sheets need to be folded into signatures. This involves a series of right-angle folds in which the sheet is folded multiple times. Folding a sheet once makes four pages, two right-angle folds make eight pages,…

Other types of work require parallel folds in which two or more folds which are oriented in the same direction are made in a sheet. This is typically done for leaflets or brochures. Some common types of folds are:

  • the half fold
  • the accordion fold
  • the gatefold
  • the French fold
  • the letter fold

There are two common types of folding machines: the knife folder, also known as a right-angle folder, and the buckle folder. In general knife folders are used for heavier stocks, while buckle folders are used for lighter paper types.

Collating and gathering

These processes involve placing (folded) sheets in the correct sequence. Collating refers to sorting individual sheets into sets. Many laser printers and copiers have a collating function. Gathering is a similar process but it involves folded signatures. Gathering machines have up to thirty slots or pockets in which signatures are fed manually or automatically. The machine then gathers the signatures into what is known as a book block. Such machines can also have a binding function, such as for instance a stitcher.

Binding

There are different ways of binding sheets together. Below are the most commonly used techniques:

  • Perfect binding: Pages are fixed to a cover or spine using glue. This process is used for paperback books, magazines, telephone guides,…
  • Saddle-stitching: Pages are bound by driving staples through the center of the spine of folded sheets. This wire binding technique is commonly used for magazines, newsletters, small catalogs,… but is limited in the number of pages that can be bound.
  • Side-stitching: This type of wire binding is less common than saddle-stitching. The staples are driven through the pages, usually parallel to the bind margin. Reports are often bound this way.
  • Thread sewing: A thread or cord is used to stitch a book block together. This is often done in conjunction with using an adhesive. Thread sewing is used for hardcover books. Afterward the book cover is attached using a technique called case binding. As with wire binding, there are two types of thread sewing: saddle-sewing and side-sewing.
  • Comb binding: The teeth of a plastic ‘comb’ are inserted into a series of slits drilled or punched into a stack of sheets. This process is often used for reports and presentations.
  • Spiral binding: A continuous wire or plastic coil is threaded through holes drilled or punched into a stack of sheets. Spiral binding is typically used for notebooks.
  • Loose-leaf binding: A set of holes is drilled in a stack of sheets which are then inserted into standard or customized ring binders or post binders. This binding technique is used for notebooks, presentations, financial reports, manuals or any other type of publication that require frequent updating.
  • Padding: the binding of a stack of sheets using a flexible adhesive so that the sheets can easily be removed. Notepads are a typical example of padding.

Decorative processes

Embossing and debossing

Embossing is the process of adding a relief image to a book cover or other printed material. Sometimes an ink or foil is used to accent the relief image. When the stamped image is left as is, this is called blind embossing. Debossing is the opposite, creating a sunken image on the substrate.

Foil stamping

Foils can be a real eye catcher when applied to book or magazines covers. This is especially true for metallic foils which reflect light and add a silvery or golden glow. Such foils are applied using a pattern on a heated die that presses a roll of foil against the substrate. Adding the foil can be combined with embossing in a process called foil embossing.

Coating

There are different types of coatings that can be applied to printed matter. Some are water-based and take time to dry, others such as ultraviolet coatings dry when exposed to light or heat. The different types of coatings include:

  • Varnishes protect and also have a decorative purpose. Depending on the effect that needs to be achieved these can be high-gloss or matte coatings. Sometimes a varnish isn’t applied to the entire surface but only used to make certain pictures, logos or text columns stand out. This is called a spot varnish.
  • Primers are used to improve the ink reception or to facilitate the application of another type of coating.
  • For packaging, barrier coatings improve the resistance to oxygen, water or chemicals.

Laminating

Laminating refers to bonding a separate material or layer of material to the printed matter. The most common type of laminating is sealing the print between two layers of a plastic material. A typical example of this are menu cards for restaurants which often need to be both sturdy and waterproof.

Edge staining

The edges of the pages of a book or catalog are sometimes colored to mark different sections. This is called edge staining. Gilding is a special case of edge staining in which gold leaf is applied to the edges of a book.

Converting

Converting refers to all of the finishing operations which transform a printed piece into another physical form. This includes bag making and box making but more general processes such as bookbinding, waxing, coating, laminating, folding, gluing or die-cutting are also considered converting operations.

Other finishing operations

Die cutting

Irregularly shaped printed matter such as coasters or labels are cut out of the substrate in a process called die cutting. The die contains knives or creasing rules that have been prepared specifically for a certain shape.

Glueing

Products like envelopes, stamps or labels need to have a remoistenable adhesive applied.

Indexing

Indexing refers to adding plastic index tabs or index thumb cuts to the edges of printed sheets. These can help readers locate specific information.


Discuss various types Book binding and write importance of Book binding

Bookbinding is the process of physically assembling a book from an ordered stack of paper sheets that are folded together into sections or sometimes left as a stack of individual sheets. The stack is then bound together along one edge by either sewing with thread through the folds or by a layer of flexible adhesive. Alternative methods of binding that are cheaper but less permanent include loose-leaf rings, individual screw posts or binding posts, twin loop spine coils, plastic spiral coils, and plastic spine combs. For protection, the bound stack is either wrapped in a flexible cover or attached to stiff boards. Finally, an attractive cover is adhered to the boards, including identifying information and decoration. Book artists or specialists in book decoration can also greatly enhance a book’s content by creating book-like objects with artistic merit of exceptional quality.

Books are like a treasure and should be handled in the same way. In order to create a book, book binding is a vital process. There are wide ranges of different binding options and printing services available in the market. These services can develop your book printing design and layout. Binding is a phenomenon that is generally used to describe the methods of securing or binding together loose page into a book. It is accomplished with stitching, staples, wire, plastic, tape or glue. Indeed, it is a labor intensive job. Thus, it will be wise to approach a streamlined service provider. They can take care of all your needs and demands while binding and printing a book.

The reputed book binders and printer provide their services not only for bookbinding, but also for binding documents of thesis, novels, catalogues, journals and many more. Now, you don’t have to travel a long distance to avail this facility. Yes, it’s true! You can hire this excellent service from the comfort of your home. At the same time, hiring this service will not create any hole in your pocket. These services are inexpensive and affordable for all economy classes.

Interestingly, there are different ways to bind your book. Simply, it is a method of availing an array of paper sheets and assembling them into a book. Few well-known ways of binding are fabric cover hard case binding, printed cover hard case binding, perfect binding, Coptic style binding, long-stitch binding and many more. In the current scenario, the perfect book binding methods get soaring popularity.

Collate

In printing, the term Collate refers to the gathering and arranging of individual sheets or other printed components into a predetermined sequence. Basically, Collating creates consistent, logical sets from multiple parts. Diagram A illustrates four sets of documents which have been collated. Diagram B illustrates four sets of documents which have not been collated.

Bear in mind that the individual parts of a print project can be collated without having to be bound or fastened together. For example, promotional packets – like those used for seminars, sales presentations, trade shows and other marketing purposes – are often collated[collated means collection, so both can be used] in advance for easy distribution. Likewise, printed instructional handouts may be collated in a particular order but are not necessarily bound or fastened together.

Gathering

In bookbinding, a section, gathering, or signature refers to a group of sheets, folded in the middle, and bound into the binding together. Gathering machines have up to thirty slots or pockets in which signatures are fed manually or automatically. The machine then gathers the signatures into what is known as a book block. Such machines can also have a binding function, such as for instance a stitcher.

The section is the basic building block of codex bindings. In Western bookbinding, sections are sewn through their folds, with the sewing thread linking each section to its neighboring sections.

The gatherings can be seen by looking at the top or bottom sides of the book, though cheaper modern books are perfect bound with no gatherings, gluing each sheet directly to the binding. The gatherings are sewn into the binding and the middle sheet of each gathering will have two or more short stretches of thread visible at the central fold.

In medieval manuscripts a gathering, or quire, was most often formed of 4 folded sheets of vellum or parchment, i.e. 8 leaves, 16 sides. The term “quaternion” (or sometimes quaternum) designates such a unit. A gathering made of a single folded sheet (i.e. 2 leaves, 4 sides) is a “bifolium” (plural “bifolia”); a “binion” is a quire of two sheets (i.e. 4 leaves, 8 sides); and a “quinion” is five sheets (10 leaves, 20 sides). This last meaning is preserved in the modern Italian meaning of quire, quinterno di carta. Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the number of sheets and pages in a gathering became more variable.

Saddle Stitching

The method of placing forms collateral to each other is called collating, Collated forms don’t share common spine and hence the individual forms need to be stitched t a common strip called saddle. One the forms are tightly stitched to the common saddle the saddle is pasted to binding cover. The binding cover is mostly a pair of hard bound board and binding cloth strip that holds these boards, saddle and pages together

In the printing industry, Saddle Stitching refers to a very popular book binding method in which folded sheets are gathered together one inside the other and then stapled through the fold line with wire staples.  The staples pass through the folded crease from the outside and are clinched between the centermost pages.  Two staples are commonly used but larger books may require more staples along the spine.

Saddle Stitching may sound like an odd name for a book binding process that places wire staples through sheets of paper but in the printing industry stapling is commonly called Stitching. Also, the collated sheets are draped over a Saddle-like apparatus during the stapling/stitching process, hence the name Saddle Stitching.

In diaries, and reference books or books with more than 80 pages this kind of binding is adapted. This is called saddle stitching. It is a lengthy process and a costly one too.

It’s probably the easiest (have you the tools) and the most economical binding method. Pages are folded, creased and stapled together (not by an ordinary stapler – a stapler with long jaws, designed specifically for saddle stitching). We often see this type of binding used for lookbooks, booklets, and magazines that have a smaller page count.

 Saddle Stitched Booklet Printing

Perfect Binding

A form of binding most often used in the types of books you find yourself reading on the train or at home, otherwise known as paperback or softcover books. Perfect bound books can also be useful for manuals, catalogues, and annuals. Pages are folded into sections (termed signatures in the industry) and glued with a heavier printed wrap-around cover into the spine using a strong adhesive. It’s not the strongest form of binding and your book won’t open flat; you’ll know a book has been poorly perfect bound when your pages start falling out.

Perhaps you’ve heard the term PUR perfect bound? Here the binding is much the same, but a stronger adhesive is used, and is what we would recommend if perfect binding is the style you’re going for. Generally, a hardback covered book would only be perfect bound, as the glue used to form your paperback or softcover books won’t adhere to the hard case spine very well.

 Perfect Binding  Perfect Binding

Section Sewn

Your most secure binding method. Here pages are folded together into sections (signatures). Each section is then sewn into the following section along the spine. The spine is then glued together for extra support and the cover then attached. A Section Sewn book, regardless of page count will be able to lay flat.

 Section Sewn Book  Section Sewing

Wire Binding/ Spiral Binding

Most of you would have bound a document throughout school or university using one of these methods. In a nutshell, holes are punched through the pages of your document near the bound edge, and held together using either wire or plastic coils. If you’re after a something a little fancier, a a document can be wire bound inside a hard cover, cloth or printed case.

 Wiro Bound Document  Wiro binding with a Hard Cover that is blind debossed. Click to enlarge.

Cased-in Wiro Binding

If you would like to hide the wire from the outside there is a solution known as a Cased-in Wiro. This technique, however, is more involved than your traditional wiro bound document, but the final result looks lovely as you can see.

 The inside of a Cased-in Wiro  Click to enlarge  A printed cover for a Cased-in Wiro bound book


What is perfect binding? Write advantages of perfect binding.

The many soft cover books that you see on the shelves at bookstores are good examples of perfect bound books. They have a square, printed spine and the cover is usually made from paper or cardstock that is heavier than the interior pages.  Plus, the cover is often clear coated to provide durability and improve appearance. In addition to authors, businesses and organizations use the perfect binding method on a variety of printing projects because of its professional appearance and relatively low cost. Perfect binding is commonly used for annual and corporate reports, manuals, catalogs, and thicker product brochures and magazines.

Benefits of Perfect Binding.

The primary benefits of perfect bound books are that they look professional and offer visual appeal, are less expensive to produce than hardcover books, and they stack well. Also, the square spinal edge formed by the perfect binding method allows for the book’s title or other information to be printed on the spine…something the saddle stitch and spiral binding methods do not offer.

In addition, perfect bound books can be printed in Short Runs and are a great candidate for On Demand Printing. This provides tremendous benefits to book authors as well as cost-conscious businesses and organizations. For more information, see our article “The Benefits of Short Run Printing / Print On Demand”

  • It is less expensive than hardcover binding methods.
  • This method will accommodate a high page count.
  • It can be used for very short production runs…for example, 150 books.
  • Books can be made with a heavier weight cover for durability and longevity.
  • This method forms a flat spinal edge which can be printed upon.
  • The finished shape allows books to stack well for storage and display.
  • Perfect binding provides a crisp, professional appearance.

The Perfect Binding Process.

To assemble a perfect bound book, your printer first stacks the interior pages together to form a crisp block. Then the spinal edge of this block is roughed up with blades or abrasives. This exposes more paper fibers and increases the bonding area for the glue. Hot glue is then applied along the roughed up edge of the interior page block. The cover of the book is then wrapped around the block of pages and it adheres to the glue along the spine. After the glue has cured, the three open edges of the book are trimmed as needed to give them nice clean edges.


Explain Gravure Printing & its advantages.

Rotogravure (roto or gravure for short) is a type of intaglio printing process, which involves engraving the image onto an image carrier. In gravure printing, the image is engraved onto a cylinder because, like offset printing and flexography, it uses a rotary printing press.

Once a staple of newspaper photo features, the rotogravure process is still used for commercial printing of magazines, postcards, and corrugated (cardboard) and other product packaging.

Gravure printing is normally a reel-fed printing method although sheet-fed machines exist in small numbers. Gravure is used mainly for large runs for magazines and directories on thinner paper. However, a significant number of applications are run on paperboard for high volume packaging such as cigarette cartons and large volume confectionery/liquid packaging.

The presses used for printing packaging applications are different from the publication presses in two ways: they are narrower and print units are almost exclusively set up in a straight sequence horizontally (magazine printers can have print units set up vertically).

Gravure printing is primarily a long-run, high-speed, high-quality printing method. Like engraving, gravure is a form of intaglio printing that produces fine, detailed images. It can be used for CMYK printing where each color of ink is applied by its own cylinder and with drying steps in between.

Like flexography, gravure printing is often used for high-volume printing of packaging, wallpaper and gift wrap. Although less common, gravure printing may also be used for printing magazines,  greeting cards, and high-volume advertising pieces.

Features

Because gravure is capable of transferring more ink to the paper than most other printing processes, it is noted for its remarkable density range (light to shadow) and hence is a process of choice for fine art and photography reproduction, though not typically as clean an image as that of offset lithography. A shortcoming of gravure is that all images, including type and “solids,” are actually printed as dots, and unless the ink and substrate combination is set up to allow solid areas to flow together, the screen pattern of these dots can be visible to the naked eye.

Gravure is an industrial printing process capable of consistent high quality printing. Since the Gravure printing process requires the creation of one cylinder for each colour of the final image, it is expensive for short runs and best suited for high volume printing. Typical uses include long-run magazines in excess of 1 million copies, mail order catalogs, consumer packaging, Sunday newspaper ad inserts, wallpaper and laminates for furniture where quality and consistency are desired. Another application area of gravure printing is in the flexible-packaging sector. A wide range of substrates such as polyethylene, polypropylene, polyester, BOPP, etc. can be printed in the gravure press. Gravure printing is one of the common processes used in the converting industry.

Rotogravure presses for publication run at 45 feet (14 m) per second and more, with paper reel widths of over 10 feet (3 m), enabling an eight-unit press to print about seven million four-color pages per hour.

The vast majority of gravure presses print on rolls (also known as webs) of paper or other substrates, rather than sheets. (Sheetfed gravure is a small, specialty market.) Rotary gravure presses are the fastest and widest presses in operation, printing everything from narrow labels to 12-foot-wide (3.66-meter-wide) rolls of vinyl flooring. For maximum efficiency, gravure presses operate at high speeds producing large diameter, wide rolls. These are then cut or slit down to the finished roll size on a slitting machine or slitter rewinder. Additional operations may be in line with a gravure press, such as saddle stitching facilities for magazine or brochure work.

Advantages

The rotogravure printing process is the most popular printing process used in flexible-packaging manufacturing, because of its ability to print on thin film such as polyester, OPP, nylon, and PE, which come in a wide range of thicknesses, commonly 10 to 30 micrometers.

Other appreciated features include:

  • printing cylinders that can last through large-volume runs without the image degrading
  • good quality image reproduction
  • low per-unit costs running high volume production

Disadvantages

Shortcomings of the gravure printing process include:

  • high start-up costs: hundreds of thousands of copies needed to make it profitable
  • rasterized lines and texts
  • long lead time for cylinder preparation, which is offsite as the techniques used are so specialized

Compare different printing technologies (processes) in terms of its merits & limitations.

There are a wide variety of technologies that are used to print stuff. The main industrial printing processes are:

  • Offset lithography
  • Flexography
  • Digital printing: inkjet & xerography
  • Gravure
  • Screen printing

Additional printing techniques were developed for very specific applications. These include flock printing, letterpress, intaglio, pad printing, and thermography.

Why a certain job is better printed using one of these processes mentioned can be read on this page about choosing a printing process.

Offset

Famously known as Offset printing this process is considered the most cost-effective that is why many in the industry prefer this process. This also allows publishers to print high quantity of prints in faster time because the printing machine is very quick and easy top set up as long as plates are already available. Basically in offset printing, the roller plates are run through water and then ink. Ink adheres to areas with images (including texts and designs) while water on the white spaces of the layout. It is then pressed to a rubber plate before pressing on a paper. One of the major drawbacks of this printing process is the plate. Once a layout is already made into a plate, omissions cannot be easily changed.

In offset lithography a printing plate, which is most often made from aluminum, contains an image of the content that needs to be printed. When the plate is inked, only this image part holds ink. That inked image is subsequently transferred (or offset) from the plate to a rubber blanket and then to the printing surface. The process can be used to print on paper, cardboard, plastic or other materials, but these have to have a flat surface.

Below is a picture of a 4 color sheetfed printing press. At the far end is the intake where individual sheets of paper are automatically fed into the press. The 4 towers or printing units each print one color, typically black get printed first, followed by cyan, magenta and yellow. The stack of printed sheets is visible on the front of the machine, underneath the press console & monitor which the press operator uses to control the press.

4 color Ryobi press

For higher volume work offset presses use rolls of paper. The picture below shows such a much larger web press. It is so fast that the printed paper needs to be force dried. The black unit at the end of the press is an oven.

Manroland web press with drying oven

Offset is nowadays the most widely used printing technique for an extensive range of products such as books, newspapers, stationery, corrugated board, posters, etc.

Using offset to print promotion, packaging, publications and on products

There is a trend that printing promotional material is gradually migrating to digital printing while some packaging printing is moving to flexo.

Flexo

In flexography the content that needs to be printed is on a relief of a printing plate, which is made from rubber. This plate is inked and that inked image is subsequently transferred to the printing surface.  The process can be used to print on paper as well as plastics, metals, cellophane and other materials. Flexo is mainly used for packaging and labels and to a lesser extent also for newspapers.

Using flexo to print promotion, packaging, publications and on products

Some packaging printing is moving from flexo to digital.


Digital printing

You will be printing a layout full of images you might want your prints to be of high quality so that the images won’t get blurry. The printing process that you should do is digital printing. This process is the most favored today because of its high quality prints and quick printing process from computer directly to the printer. Plates are not needed on digital printing so it needs lesser man power. This process however is expensive because of the ink and paper used by the printer. The colors can also be difficult to adjust or predict since the colors of the image to be printed might be different on the computer monitor.

Digital printing can be done in various ways. Two technologies dominate the industry:

  • Inkjet – In an inkjet printer the image that needs to be printed is created by small droplets of ink that are propelled from the nozzles of one or more print heads. Inkjet devices can print on a wide range of substrates such as paper, plastic, canvas or even doors and floor tiles.Inkjet printing is used a lot for posters and signage. It is also economical for short run publications such as photo books or small runs of books. In-line inkjet printers are sometimes combined with other types of presses to print variable data, such as the mailing addresses on direct mail pieces.  The press shown below is the HP PageWide C500, meant for printing on corrugated board.

HP PageWide C500 Press

  • Xerography – In xerographic printers, such as laser printers, the image that needs to be printed is formed by selectively applying a charge to a metal cylinder called a drum. The electrical charge is used to attract toner particles. These particles are transferred to the media that is being printed on. To make sure the toner is fixed properly, the substrate passes through a fuser that melts the toner into the medium.Laser printers are not only used in offices but also for small run printing of books, brochures and other types of document. These printers are also used for transactional printing (bills, bank documents, etc) and direct mail.

In 2009 both techniques jointly accounted for around 15% of the total volume of print.

Using digital printing for promotion, packaging, publications and products


Digital printing is increasingly utilized for print jobs that were previously printing using offset, flexo or screen printing.

  • In short run small format (A3 size) printing, digital is taking over from offset for both color and B&W printing. Quick printers and copy shops print digitally on presses from vendors like Xerox, HP, Canon, and Konica Minolta.
  • Labels are also increasingly being printed digitally.
  • Billboard and point-of-sale or point-of-purchase jobs are being done by wide-format inkjet devices.
  • There is a wide range of small format printers used to print on phone cases, mugs and other products.
  • In book printing publishing companies start to rely more on print-on-demand. The Espresso Book Machine pictured below is well suited for that job.

There are a number of other digital printing processes that are geared towards specific niche markets:

  • Dye-sublimation is a printing process in which heat is used to transfer a dye onto the substrate. Dye-sub printers are mainly used for printing on textiles, for proofing and for producing photographic prints. Some printers can print on a variety of materials such as paper, plastic, and fabric.
  • In the direct thermal printing process heat is used to change the color of a special coating that has been applied to paper. This process is used in cash registers but also to add markings, such as serial numbers, to products. For this a transparent ink is used that changes color when a laser applies heat to it.
  • In the thermal ink transfer printing process heat is used to melt print off a ribbon and onto the substrate. It is used in some proofing devices but seems to be gradually disappearing off the market.

Gravure

Also known as rotogravure, this is a technique in which an image is engraved into a printing cylinder. That cylinder is inked and this ink subsequently transfers to the paper.  Gravure is used for high volume work such as newspapers,  magazines, and packaging.

Using rotogravure to print promotion, packaging, publications and on products

Gravure is gradually losing market share to offset for publication printing and to flexo for packaging applications.

Screen printing

As its name implies, this printing technique relies on a screen, which is a woven piece of fabric. Certain areas of this mesh are coated with a non-permeable material. In the remaining open spaces ink can be pushed through the mesh onto a substrate. The advantage of screen printing is that the surface of the recipient does not have to be flat and that the ink can adhere to a wide range of materials, such as paper, textiles, glass, ceramics, wood, and metal.

The image below shows a screen printing press that is used to print t-shirts.

Press that is used to print t-shirtsIncreasingly screen printing is being replaced by digital printing.

Additional printing processes

  • Letterpress – Once a dominant printing technique, letterpress is now used for business cards, wedding invitations,…
  • Flocking – used to add a (colored) velvet-like texture to paper, textiles, etc.
  • Pad printing – used to print on 3-dimensional surfaces.
  • Intaglio – nowadays mainly used for used stamps and paper currency.
  • Thermography – This is more of a finishing process than an actual printing process. It produces raised lettering on the printed side of the paper and is used for wedding invitations, letterheads, business cards,…

Dots vs Pixels

In today’s age of digital terminology, it is quite easy to mix up pixels and dots. Pixel is the term in digital imaging and it is the tiniest part of a photography whether taken from digital camera or scanned with modern scanners. The dot is printing term and refers to smallest printable part of an image with ink

  •  Pixels are tightly places squares touching each other while the dots are spaced. The space between the dots may vary according to the halftone method used
  • Pixels have varying tone from 0 to 255, while the dots have fixed tone of the ink colour and do not vary
  • Pixels are seen on monitor when the image is enlarged or in photographic printing when printed in colour lab or by Laser Printing Method. On the other hand, dots are seen on printed page only when seen through magnifying glass if it is printing
  • Pixel Resolution is termed as Pixel Per Inch, it is the number of pixels per linear inch. While Dot Resolution is termed as Dots Per Inch, where it is the number of lines perpendicular to the angle of the screen or dots per linear inch at an angle parallel to the screen.

Screens can be a coarse or fine, depending on the paper that is to be used. The rougher is the paper coarser is the required screen. The number used to describe the screens is the number of lines per inch. For example, 133LPI has 133 Lines Per Inch and considered to be fine, not finest though. Most commercial magazine and book printing on reasonable paper use 133LPI. But newspaper on the contrary uses as low as 65LPI

Resolution

The term resolution describes the number of dots, or pixels, that an image contains or that can be displayed on a computer monitor, television, or other display device. These dots number in the thousands or millions, and clarity increases with resolution. Resolution is a measure used to describe the sharpness and clarity of an image or picture and is often used as a metric for judging the quality of monitors, printers, digital images and a various other hardware and software technologies. The term is especially popular in the mobile industry for describing a mobile device’s display capabilities, and also in the entertainment media to distinguish the visual quality of movies and to distinguish between high definition and standard definition movies.

In printing, the term Resolution refers to the sharpness and detail of images. Higher resolution means more image detail. Lower resolution means less image detail.

Generally speaking, resolution is the degree to which the eye can distinguish the varying components of an image. On a more technical level, the term resolution refers to a numerical measure of the clarity and sharpness a device, such as a computer monitor or printing press, can create an image. Common measures of resolution include pixels per inch (PPI) and dots per inch (DPI).

Web Images

Web images are digital images. Thus, they are created from electronic pixels. Pixels are little individual box-shaped units of color that bump up next to each other to create visually recognizable images such as photos or text. The resolution of web images is generally 72 PPI (pixels per inch), which is regarded as low resolution.

Because lower resolution images contain less detail, they take up less storage space and load quicker on a display screen…which are good traits for website images. However, less detail is a bad trait for printed images. So as a general rule, images from websites do not reproduce well when printed.

Printed Images

A printing press works by applying dots of ink or toner onto paper. The varying colors of these dots and their spatial relationship create the printed images we recognize as photographs or designs. The more dots that are used, the sharper and cleaner the image (up to a point). Most digital and offset printing presses print at a resolution of 300 DPI (dots per inch). 300 DPI is considered high resolution and the minimum DPI for quality printed output.

Since the high resolution artwork files used for printing are created with graphics software, they originally exist in digital (pixel) form. High resolution files are generally large in size because they contain so much detail, but that’s okay when it comes to printing. Prior to press output, sophisticated software converts the color information of each pixel into the various dots needed to recreate the artwork onto the printed piece.


LPI & Screen Angle

Screen Angle

In offset printing, the screen angle is the angle at which the halftones of a separated color is made output to a lithographic film, hence, printed on final product media.

Screen is like a fine mesh of lines and lines run at right angles to each other like rows and columns. The Gap is Transparent and this allows image areas to get exposed on the film. If the screen is places such that the rows are horizontal and columns are vertical then the screen becomes noticeable in the image and the desired smoothness of the image is lost. This is because the natural movement of our eye and the horizontal and the resolving efficiency of eye is maximum for objects arranged horizontally. This is why the screen for black and white image is placed at 45 Degree so that the screen will not be evident in printed image.

 

Compare the two squares above. In the left square the screen is noticeable as discipline rows and column but in square to right it is a uniform pattern without noticeable rows and columns. This is the basic of minimizing screen visibility.

LPI

Lines per inch (LPI) is a measurement of printing resolution. A line consists of halftones that is built up by physical ink dots made by the printer device to create different tones. Specifically LPI is a measure of how close together the lines in a halftone grid are. The quality of printer device or screen determines how high the LPI will be. High LPI indicates greater detail and sharpness.

Printed magazines and newspapers often use a halftone system. Typical newsprint paper is not very dense, and has relatively high dot gain or color bleeding, so newsprint is usually around 85 LPI. Higher-quality paper, such as that used in commercial magazines, has less dot gain, and can range up to 300 LPI with quality glossy (coated) paper.

In order to effectively utilize the entire range of available LPI in a halftone system, an image selected for printing generally must have 1.5 to 2 times as many samples per inch (SPI). For instance, if the target output device is capable of printing at 100 LPI, an optimal range for a source image would be 150 to 200 SPI. Using fewer SPI than this would not make full use of the printer’s available LPI; using more SPI than this would exceed the capability of the printer, and quality would be effectively lost.

The screen determines the quantity of ink consumed per impression. High resolution screen has more number of dots and the ink requirement becomes higher as that much number of dots will consume ink per inch. High resolution cost is higher for the consumption of ink as well as requirement of finer paper


Web fed & Sheet fed

One printing decision that is often overlooked is whether to use a sheet fed printer or go with web based printing instead. There are some very important differences between these methods, and each one may be the best method in some situations but less ideal in others. Which one is best for your next project? Read on to find out.

A Sheet Fed Printer Uses Individual Paper Sheets

A sheet fed printer traditionally required individual sheets of paper to be manually fed into the equipment. Thanks to constantly-advancing printing technology, this is not always the case today. Now it is possible for a roll of paper to be used.

Using a paper roll, equipment cuts the roll into individual sheets that are automatically fed into the printing machinery. As you might imagine, using a roll of paper is less labor-intensive than feeding in hundreds of separate sheets.

Even when it uses a roll, this type of printer is still referred to as a sheet fed printer.

Advantages of Sheet Fed Printing

Some of the advantages that you can get from using a sheet fed printer include:

  • Special finishes can be accommodated
  • Sheets can be printed twice instead of just once
  • Less waste to set up and prepare for the printing process
  • Thicker or higher weight stocks of board and paper can be used
  • High quality results
  • Fast set up (although it does have a slower production speed once production begins)
  • Can be economically used for small print runs and low volume orders

A Web Printer Uses Large Paper Rolls

Unlike a sheet fed printer, web printing has always involved using large paper rolls. These rolls of stock create a web that is continuously fed into the printing equipment. The roll is cut into the appropriate size after printing is complete. Using a web printer can be very cost-effective for large orders, but it is typically not used for orders of less than 6,000 items.

Advantages of Web Printing

A web printer offers different advantages than a sheet fed printer, and it can be used in different ways. Some of the possible web printing advantages include:

  • Faster production speed than the sheet fed process, although the web method does take more time and effort in set up and pre-production
  • Lower weight and thinner stocks can be used
  • Typically offers a faster turnaround time than sheet printing when it comes to larger orders
  • Images have a high quality regardless of the paper stock used
  • Web printing offers in-line folding as an option
  • Can offer better image lift

Gathering & Collating

Collate

In printing, the term Collate refers to the gathering and arranging of individual sheets or other printed components into a predetermined sequence. Basically, Collating creates consistent, logical sets from multiple parts. Diagram A illustrates four sets of documents which have been collated. Diagram B illustrates four sets of documents which have not been collated.

Bear in mind that the individual parts of a print project can be collated without having to be bound or fastened together. For example, promotional packets – like those used for seminars, sales presentations, trade shows and other marketing purposes – are often collated in advance for easy distribution. Likewise, printed instructional handouts may be collated in a particular order but are not necessarily bound or fastened together.

Gathering

In bookbinding, a section, gathering, or signature refers to a group of sheets, folded in the middle, and bound into the binding together. Gathering machines have up to thirty slots or pockets in which signatures are fed manually or automatically. The machine then gathers the signatures into what is known as a book block. Such machines can also have a binding function, such as for instance a stitcher.

The section is the basic building block of codex bindings. In Western bookbinding, sections are sewn through their folds, with the sewing thread linking each section to its neighboring sections.

The gatherings can be seen by looking at the top or bottom sides of the book, though cheaper modern books are perfect bound with no gatherings, gluing each sheet directly to the binding. The gatherings are sewn into the binding and the middle sheet of each gathering will have two or more short stretches of thread visible at the central fold.

In medieval manuscripts a gathering, or quire, was most often formed of 4 folded sheets of vellum or parchment, i.e. 8 leaves, 16 sides. The term “quaternion” (or sometimes quaternum) designates such a unit. A gathering made of a single folded sheet (i.e. 2 leaves, 4 sides) is a “bifolium” (plural “bifolia”); a “binion” is a quire of two sheets (i.e. 4 leaves, 8 sides); and a “quinion” is five sheets (10 leaves, 20 sides). This last meaning is preserved in the modern Italian meaning of quire, quinterno di carta. Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the number of sheets and pages in a gathering became more variable.


Subtractive Colour Theory

Did not find answer. Found Meaning of Color Theory

A subtractive color model explains the mixing of a limited set of dyes, inks, paint pigments or natural colorants to create a wider range of colors, each the result of partially or completely subtracting (that is, absorbing) some wavelengths of light and not others. The color that a surface displays depends on which parts of the visible spectrum are not absorbed and therefore remain visible.

Subtractive color systems start with light, presumably white light. Colored inks, paints, or filters between the watchers and the light source or reflective surface subtract wavelengths from the light, giving it color. If the incident light is other than white, our visual mechanisms are able to compensate well, but not perfectly, often giving a flawed impression of the “true” color of the surface.

Conversely, additive color systems start with darkness. Light sources of various wavelengths are added in various proportions to produce a range of colors. Usually, three primary colors are combined to stimulate humans’ trichromatic color vision, sensed by the three types of cone cells in the eye, giving an apparently full range.


Process colours

Four color process printing is a system where a color image is separated into 4 different color values (called a color separation) by the use of filters and screens. This used to be done with photographic film on a graphic arts camera, but is usually done digitally with software now.

The result is a color separation of 4 images that when transferred to printing plates and sequentially printed on a printing press with the colored inks cyan (blue), magenta (red), yellow and black (the k in cmyk), reproduces the original color image. Most of the entire spectrum or gamut of colors are reproduced with just the four process ink colors. The four color printing process is universally used in the graphic arts and commercial printing industry for the reproduction of color images and text.

CMYK Process Printing Features

  • It uses the same 4 standardized base colors all the time (cyan, magenta, yellow and black)
  • Small dots of these colors are printed at different angles to create the printed image
  • The most widely used and cost effective color system in commercial printing
  • It’s significantly cheaper than toner based or digital printing for larger quantity runs

The use of color in print increases readership and information retention.

Studies in a major publication revealed that the use of color increased readership by 40% or more. A university study showed a 65% increase in the retention of material when full color was used instead of black and white.

Spot color printing creates brighter, more vibrant results, but with a smaller color range. When printing in single (spot) colors, a single color ink (normally with a Pantone reference number) is applied to the printing press roller. If there is just one color to be printed, there will be a single plate, and a single run of the press. If there are two colors, there will be two plates and two runs, and so on. The colors are layered onto the paper one by one.

Spot color printing would be typically used for jobs which require no full color imagery, such as for business cards and other stationery, or in monotone (or duotone etc) literature such as black and white newspaper print.

4 color process printing involves the use of four plates: Cyan, Magenta, Yellow and Keyline (Black). The CMYK artwork (which you will have supplied) is separated into these four colors – one plate per color. The four CMYK inks are applied one by one to four different rollers and the paper or card (‘stock’) is then fed through the printing press. The colors are applied to the stock one by one, and out comes the full color (4 color process) result.

Here is an example of 4 color process printing and three examples of spot color printing. There is a lot of versatility in designing for a spot color print run – experiment and see what results you can achieve!


Offset cylinder

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CTP Technology

CTP is an imaging technology used in modern printing processes. In this an image created in Desktop Publishing Application is output directly to a printing plate instead of going through a negative positive lithographic film. Lithographic film was used to expose the polymer plate to cast image onto it and later chemically developed. The method was similar to contact printing in photography darkroom. The eliminating of this optical process process saves time in steps and drying as well as saves what is called generation loss in quality.

Computer design directly imprints the images onto this CTP Plate just like a domestic printer prints image onto paper. Only difference is that it doesn’t print ink but creates desired chemical difference of water absorbent and not absorbent. The plate maker is far larger than our domestic printer to get a plate size of largest printable format on offset


Halftone

Halftone is a process of breaking down the image into a structure of tiny dots of constant tone. Colour filtered images are still in continuous tones & only four inks cannot produce more colours directly. To make this possible, the images undergo a process called halftone which breaks the image into tiny dots of fixed tone. This is binary conversion so that in single impression with one ink varied values can be printed. These varied values are outcome of interplay of whiteness of paper & colour of ink. The density of dots at a place decides tone of that place, Thus a halftone image appears full tone when all four colours make impression on paper


Pagination

Pagination is a process of arranging pages onto a larger printable page order so that after binding the pages fall in numeric sequence ar bigger than the actual page format (size). This helps many pages to be printed in one impression. Taking advantage of this the pages are arranged in such a way that once the printed page is folded the next page falls in consecutive number to make a folder, or a book.

Pagination is the process of dividing a document into discrete pages, either electronic pages or printed pages.

In reference to books produced without a computer, pagination can mean the consecutive page numbering to indicate the proper order of the pages, which was rarely found in documents pre-dating 1500, and only became common practice c. 1550, when it replaced foliation, which numbered only the front sides of folios.

Today printed pages are usually produced by outputting an electronic file to a printing device, such as a desktop printer or a modern printing press. These electronic files may for example be Microsoft Word, PDF or QXD files. They will usually already incorporate the instructions for pagination, among other formatting instructions. Pagination encompasses rules and algorithms for deciding where page breaks will fall, which depend partly on cultural considerations about which content belongs on the same page: for example one may try to avoid widows and orphans. Some systems are more sophisticated than others in this respect. Before the rise of information technology (IT), pagination was a manual process: all pagination was decided by a human. Today, most pagination is performed by machines, although humans often override particular decisions (e.g. by inserting a hard page break).

The operator will also use this sheet to check for pagination, or the order of pages, by folding the parent sheet to final-product size. This process confirms that all the pages will be printed in the proper order and that they will appear right-side up when bound together.


Web fed & Sheet fed

One printing decision that is often overlooked is whether to use a sheet fed printer or go with web based printing instead. There are some very important differences between these methods, and each one may be the best method in some situations but less ideal in others. Which one is best for your next project? Read on to find out.

A Sheet Fed Printer Uses Individual Paper Sheets

A sheet fed printer traditionally required individual sheets of paper to be manually fed into the equipment. Thanks to constantly-advancing printing technology, this is not always the case today. Now it is possible for a roll of paper to be used.

Using a paper roll, equipment cuts the roll into individual sheets that are automatically fed into the printing machinery. As you might imagine, using a roll of paper is less labor-intensive than feeding in hundreds of separate sheets.

Even when it uses a roll, this type of printer is still referred to as a sheet fed printer.

Advantages of Sheet Fed Printing

Some of the advantages that you can get from using a sheet fed printer include:

  • Special finishes can be accommodated
  • Sheets can be printed twice instead of just once
  • Less waste to set up and prepare for the printing process
  • Thicker or higher weight stocks of board and paper can be used
  • High quality results
  • Fast set up (although it does have a slower production speed once production begins)
  • Can be economically used for small print runs and low volume orders

A Web Printer Uses Large Paper Rolls

Unlike a sheet fed printer, web printing has always involved using large paper rolls. These rolls of stock create a web that is continuously fed into the printing equipment. The roll is cut into the appropriate size after printing is complete. Using a web printer can be very cost-effective for large orders, but it is typically not used for orders of less than 6,000 items.

Advantages of Web Printing

A web printer offers different advantages than a sheet fed printer, and it can be used in different ways. Some of the possible web printing advantages include:

  • Faster production speed than the sheet fed process, although the web method does take more time and effort in set up and pre-production
  • Lower weight and thinner stocks can be used
  • Typically offers a faster turnaround time than sheet printing when it comes to larger orders
  • Images have a high quality regardless of the paper stock used
  • Web printing offers in-line folding as an option
  • Can offer better image lift

Impostition

Imposition is one of the fundamental steps in the prepress printing process. It consists of the arrangement of the printed product’s pages on the printer’s sheet, in order to obtain faster printing, simplify binding and reduce paper waste.

Correct imposition minimizes printing time by maximizing the number of pages per impression, reducing cost of press time and materials. To achieve this, the printed sheet must be filled as fully as possible.

Imposition for commercial jobs

Commercial printing includes producing catalogs, magazines, brochures, leaflets, flyers, stationery, business cards as well as posters and billboards.

Imposing signatures

For multipage documents such as magazines or brochures, all the pages are combined in signatures, which are printed sheets that are folded to the required page size.

The example below shows an imposition scheme that can be used for imposing 8 A4 pages on an SRA1 sized sheet.

impositon - example of a signature

Signatures contain multiple pages. An imposition scheme determines how those pages will be positioned on the signature. How many pages are combined, how these are positioned and which additional information is added to the signature is determined by many parameters:

1. Page and sheet size

On a press capable of printing on SRA1-sized sheets, which measure 640×900 mm, you can put 8 A4-size pages. The ability to print 8 A4 or Letter size pages in one go is called an 8-up. There are 2-up, 4-up, 8 up,… devices.

2. The number of pages of the printed product

The compositor must determine how many sheets are to be printed to create a finished book. Some products, such as digitally printed

3. Job content

It doesn’t happen very often but sometimes the content of pages, such as large flat tints or dark images, require a change in the imposition template to make the job easier to print.

4. Printing press

The choice of printing press has a major impact on the imposition process. It affects both the work style and the position of the pages on the sheet.


Digital printing

Digital printing refers to methods of printing from a digital-based image directly to a variety of media. It usually refers to professional printing where small-run jobs from desktop publishing and other digital sources are printed using large-format and/or high-volume laser or inkjet printers. Digital printing has a higher cost per page than more traditional offset printing methods, but this price is usually offset by avoiding the cost of all the technical steps required to make printing plates. It also allows for on-demand printing, short turnaround time, and even a modification of the image (variable data) used for each impression. The savings in labor and the ever-increasing capability of digital presses means that digital printing is reaching the point where it can match or supersede offset printing technology’s ability to produce larger print runs of several thousand sheets at a low price.

The greatest difference between digital printing and traditional methods such as lithography, flexography, gravure, or letterpress is that there is no need to replace printing plates in digital printing, whereas in analog printing the plates are repeatedly replaced. This results in quicker turnaround time and lower cost when using digital printing, but typically a loss of some fine-image detail by most commercial digital printing processes. The most popular methods include inkjet or laser printers that deposit pigment or toner onto a wide variety of substrates including paper, photo paper, canvas, glass, metal, marble, and other substances.

In many of the processes, the ink or toner does not permeate the substrate, as does conventional ink, but forms a thin layer on the surface that may be additionally adhered to the substrate by using a fuser fluid with heat process (toner) or UV curing process (ink).


Variable Data Printing

Variable–data printing (VDP) (also known as variable–information printing (VIP) or variable imaging (VI)) is a form of digital printing, including on-demand printing, in which elements such as text, graphics and images may be changed from one printed piece to the next, without stopping or slowing down the printing process and using information from a database or external file. For example, a set of personalized letters, each with the same basic layout, can be printed with a different name and address on each letter. Variable data printing is mainly used for direct marketing, customer relationship management, advertising, invoicing and applying addressing on selfmailers, brochures or postcard campaigns.

VDP is a direct outgrowth of digital printing, which harnesses computer databases and digital print devices and highly effective software to create high-quality, full color documents, with a look and feel comparable to conventional offset printing. Variable data printing enables the mass customization of documents via digital print technology, as opposed to the ‘mass-production’ of a single document using offset lithography. Instead of producing 10,000 copies of a single document, delivering a single message to 10,000 customers, variable data printing could print 10,000 unique documents with customized messages for each customer.

The returns for variable printing vary from double the normal return at the basic level to 10–15 times the return for fully variable jobs.[citation needed] This naturally depends on content and the relevancy of that content, but the technique presents an effective tool for increasing ROI on marketing campaigns.

There are several levels of variable printing. The most basic level involves changing the salutation or name on each copy much like mail merge. More complicated variable data printing uses ‘versioning’, where there may be differing amounts of customization for different markets, with text and images changing for groups of addresses based upon which segment of the market is being addressed. Finally there is full variability printing, where the text and images can be altered for each individual address. All variable data printing begins with a basic design that defines static elements and variable fields for the pieces to be printed. While the static elements appear exactly the same on each piece, the variable fields are filled in with text or images as dictated by a set of application and style rules and the information contained in the database.

There are three main operational methodologies for variable data printing.

In one methodology, a static document is loaded into printer memory. The printer is instructed, through the print driver or raster image processor (RIP) to always print the static document when sending any page out to the printer driver or RIP. Variable data can then be printed on top of the static document. This methodology is the simplest way to execute VDP, however its capability is less than that of a typical mail merge.

A second methodology is to combine the static and variable elements into print files, prior to printing, using standard software. This produces a conventional (and potentially huge) print file with every image being merged into every page. A shortcoming of this methodology is that running many very large print files can overwhelm the RIP’s processing capability. When this happens, printing speeds might become slow enough to be impractical for a print job of more than a few hundred pages.

A third methodology is to combine the static and variable elements into print files, prior to printing, using specialized VDP software. This produces optimized print files, such as PDF/VT, PostScript or PPML, that maximize print speed since the RIP only needs to process static elements once.

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