• Publishing & printing

Ed #10 Prepress

Ed™ knows prepress. Ed thinks you should get everything you want, all of the time. For designers and other graphic arts professionals, there are few better feelings than seeing a job come off press, looking exactly as you wanted it to—just as you saw it in your imagination.

The challenge is getting to that point. Ed can give you a hand, right from the start. In this issue—and the next—Ed will look at the printing process, from your initial talk with the client through the final press OK. Ed will explore how to work with printers, how to get the most out of electronic prepress technology—and avoid some common mistakes—and how to get the exact results you’re looking for. Of course the subject is complex, and not even Ed can make you an expert overnight. But you’re sure to learn something new about getting ready for the press and some useful tips to apply to your next project.

Why does Ed do it? Because Ed loves print. Because even in the age of electronic communications, ink on paper can still deliver unmatched interest and impact. And Ed wants to help you make the most of print’s creative possibilities—and make every project stand out.

Ed will never grow old, but some of the information in this issue is out of date.

Preparation. It takes a lot to get a project ready for press. Most of all, it takes communication.

Prepress Timeline Game



Successful printing begins long before the job goes on press, with RIPping, trapping, preflighting, and a lot of questions.


In case their younger colleagues don’t already know it, the senior graphic designers they’re working with today came from a different place. Most began their careers at drawing boards, with an X-Acto® knife and a jar of rubber cement. Working as keyliners or mechanical artists, often the first step in a design career, they glued or waxed photostatic prints and columns of type supplied by a typesetter onto illustration boards. The boards and any color art were photographed using special cameras to produce separations. If retouching was required, it was performed with an airbrush, bleach or by etching the dots on the separation films. Film strippers combined line art and separations to assemble the final film.

Then, in the 1980s, everything changed. The first electronic typesetters, which used lasers to produce type on film, evolved into imagesetters that could electronically reproduce both type and images. Soon, “desk-top” publishing systems allowed anyone with a computer to take over much of the work of keyliners, typesetters, film strippers and retouchers, whose jobs changed beyond recognition or were eliminated entirely. The revolution continued as prepress processes became almost completely electronic, with projects rarely touching paper until they were printed.

Yet, while much has changed, success begins where it always has—with effective communications. Completing a printing project successfully still means sharing your thoughts, opinions, requirements and information. You still need what you always needed, which are answers to, oh, about 1,000 questions.

The questions begin the moment the job does, with the first talks with your client. A little time with the client’s existing publications or on the Web will provide some background information, but that’s only the start. When you’re taking on a project, especially one for a new client, it’s virtually impossible to ask too many questions. Along with asking about schedules, quantities, and other practical matters, you should try to get the bigger picture: What’s the background of the project? Who is the audience? What are the key messages? How does the client want to be perceived? It’s hard to predict where an idea will come from, so the more you can get your client talking, the better. Then ask, “Is there anything else we should be discussing?”

Almost always, designing a project and planning for its production are intertwined from the start. It’s difficult to develop concepts or a design until you have a sense of the schedule and budget as well as your client’s objectives. If the deadline is short, you may need to skip the global photo shoot in favor of stock images. A tight budget might rule out the use of metallic inks or spot colors.

As the answers you get begin to shape the design and the specifications, it’s time to start talking with your printer or, more often, your printer’s sales representative. It’s never too soon to make contact, especially if you’re looking for advice as well as an estimate. The printer’s representative will likely ask about schedule, colors, quantities, trim size, the number of pages, type and size of any images, paper choices, special inks or coatings, finishing and binding, and your plans for distribution or shipping. Virtually every choice can affect the entire process. The way that the project is bound, for example, will have an impact on layout dimensions, finished trim sizes, and possibly the design itself. Special stocks, coatings or finishing techniques can add days or weeks to production schedules.

Your talks with the printer shouldn’t stop at the specifications. You should also discuss how you’ll be supplying material to make sure the printer’s systems can handle it. And you should be asking questions, too. Do any elements of the proposed design present any potential problems? Talk about the look you’re after—the printer may have suggestions on how to achieve it. He or she also might be able to provide samples of similar projects. You should also ask for a paper dummy—or dummies—to get an idea of what the job will feel like or to compare different stocks.

Armed with the information you’ve supplied, the printer’s representative will begin to work on an estimate and schedule the job. Typically, working with others in the shop, he or she can determine what equipment, web or sheetfed, will be used to produce the job and how it will be printed. If you’re printing a job that features lots of textiles, for example, the printer may recommend stochastic, or FM screening, since FM screens help reduce the risk of moirés. If the run contains personalized information, the printer may recommend digital presses.

While there have never been more tools to produce your vision in print, the roles of the people involved are less well-defined than in the past, so you may need to consider who does what. If you provide the printer with scans of art or illustrations, you may save money, but you also will be responsible for any problems that arise—or for paying to fix them. The same goes for color correction and retouching—will it be performed by you, the photographer or the printer? Don’t forget proofreading, either. The lack of adequate proofreading is the most common cause of budget-busting alterations and costly reprints.

The estimate should also include a timeline, indicating when the printer needs materials and approvals from you in order to complete the project on time, without overtime charges. Then you can incorporate those dates into the master schedule, which lists all of the deadlines needed to complete the project, including those for client comments and approvals.

While you’ve been working on all of that, you’ve also been developing the design. That usually means working with a variety of software programs, from word processing programs that create documents to image manipulation programs, such as Photoshop,® that allow for the manipulation of type, color and images. The elements created by those programs are brought together in page layout programs that assemble them for printing.

Volumes have been written about each of these software programs, and summarizing them, even briefly, is too big a job for Ed. But it’s important to know a few terms that help explain how things work.

The most basic element in digitized images is the bitmap, also known as a pixel, short for picture element. Pixels are tiny black and white or colored squares that are arranged together like mosaic tiles to form images. Black and white pixels are formed with only one bit of information—zero or one. Images containing grays or colors need more bits of information, as many as 24 bits per pixel, to reproduce high quality color.

When an image is scanned or captured by a digital camera, the number of pixels that are saved (measured by pixels per inch, or ppi) determines the resolution of the image. The greater the number of pixels, the higher the resolution of the image, and the more computer storage space it requires.

While bitmaps are used for photos, vector graphics are usually used to reproduce illustrations, logotypes and other line art. Rather than telling the printer exactly where to place each pixel, vector graphics are mathematically generated and can scale up and down smoothly, with no loss of quality, and none of the saw-toothed edges that can be seen on enlarged bitmapped images.

Once an image is created there are a variety of ways to store, transfer, and print it. One of the most common is a JPEG, for Joint Photographic Experts Group. JPEGs have become the standard for compressing continuous tone color or black and white images. While JPEGs work well for sharing vacation photos online, they can cause problems for printers, because they are most often “lossy,” which means that when the image is compressed to make it easy to send, it discards data from the image that can never be retrieved. What’s more, each time a JPEG image is resaved, it is recompressed, which will cause further deterioration of the image.

Another way to store and transmit images is known as TIFF, for Tagged Image File Format. TIFF images are easily imported into a large number of applications including QuarkXPress® and Adobe® InDesign.® TIFF files promise lossless compression with no impact on the quality of the image. The amount of compression may be limited, however, and TIFF images can take a relatively long time to transfer online.

More than any other single technology, Adobe® PostScript® provides the foundation for modern prepress processes. PostScript is a computer language that describes how the pages of a document should look.

PostScript has largely given way to the Portable Document Format or PDF. A file format rather than a programming language, PDFs combine a special type of PostScript language with a system that allows fonts to be transferred accurately and a storage system that bundles everything together and allows it to be compressed.

Although PDF files can contain vector graphics, text and bitmapped images, they require only a fraction of the memory space of original or TIFF files. PDF files are also device independent, so they can be shared, viewed, navigated and printed by anyone with the right free software, on any computer. What’s more, the same file can be used for proofing, image setting and digital printing.

As the files are completed and the client signs off on the project, the action begins to shift to the printer. The exact steps in the process, or workflow, vary according to the type of project and the type of technology that is used. A traditional analog workflow that generates printing plates from film will have more steps and different methods of proofing than computer-to-plate or computer-to-press workflows.

Almost always, however, the first step is preflighting. “Preflighting” is a term borrowed from the procedures that pilots follow before taking off. Its aim is to discover any problems that may cause your project to crash. Most preflighting combines specialized software programs with manual checks geared to the printer’s particular workflow. Preflighting checks for both the quality of the files and their compatibility with the printer’s systems as well as such problems as lack of sufficient bleed, wrong page sizes or font problems. If problems are found, the printer will return the files for corrections or fix the problem and, often, charge for the service.

Formal preflighting is a sophisticated process. It takes experience to know how to repair and correct digital files and best construct jobs for efficient output. For that reason, most printers perform preflighting as a standard part their services.

But that doesn’t mean you can take it easy. To save time and avoid extra charges, use the built-in collection features on Quark (Collect for Output) and InDesign (Package) when submitting a project—both generate a basic preflight report, which warns of font and image issues. Make sure you have used the actual fonts from the font menu, not simply applied a style, such as “Italic,” from the style menu.

It’s also up to you to provide the very best files you can, with all changes made, and a full-size hard copy proof. If you send a PDF along with your application files, check the PDF against the laser proof for consistency and accuracy. Indicate the For Position Only (FPO) images that need to be replaced with high-resolution or retouched versions. Include crop and size instructions for any images your printer will be scanning. Make sure your files are free of viruses.

With everything transferred to the printer, you’re ready for the next step. Usually, that means additional work on the files. It may be necessary to revise or correct the text or retouch some of the images. The printer may recommend Gray Component Removal, which is described in example “Lose the Gray”. The images may also be trapped (see example, “Trapped”), and the entire project will be imposed (see chart, A Big Imposition).

Trapping and impositions are often performed as part of RIPping, or raster image processing. Raster Image Processors (RIPs) convert the data in the file to a bitmap that is used to create the image on the proofs, printing film or plates, or, in digital, toner-based systems, the electrostatic drum.

After the project is RIPped you’ll begin what can seem like an endless cycle of proofing and corrections. A proof is simply a preview of the job at various points along the way, before it is printed. And because it is always desirable to spot problems earlier rather than later, you should proof early and often.

You’ll see different types of proofs depending on how the project is prepared for press, the type of press that will be used and where you are in the process. Analog proofs are made from the film separations used to create an image on the printing plates. Digital proofs are made from the digital file, without film. While the first digital proofs were fairly crude, their quality now can surpass that of conventional systems. Some digital systems can even produce proofs with individual halftone dots.

The first proof you’re likely to see is a laser proof from a desktop laser printer. Although some laser printers can be equipped to accurately render color, most desktop proofs are used simply to check content. You can make sure that the copy and other elements are in the right place, and, if not, make changes at a minimal cost.

Image proofs, also known as random or loose color proofs, show only the printed images, without any other design elements. Are they the right size and cropped correctly? Do they match the original artwork? Is the color right? Are spot or customer colors reproduced accurately? If the image has been retouched, does it look as it should?

Bluelines, or single-color proofs, are made from the same film negatives or electronic file that will be used to image the plates or charge the image drum. Look for broken lines of type or other typographical errors. Check the pagination; make sure that any previous changes have been picked up. And when you are giving changes to the printer, make sure that all of the changes appear on a single blueline, not several different copies that need to be compared and reconciled.

As jobs get closer to the press, printers use a variety of proofing systems to simulate the color—and sometimes the dots—that will be printed. Composed proofs allow you to check for content, design and color. Make sure that all fonts, bleeds and crossovers are correct. Confirm that the right images have been used—and cropped correctly—and that large areas of ink coverage look smooth and rich. Watch out for moirés, and remember that they do not show up on monitors.

Contract proofs and press proofs are at the top of the proofing food chain. Contract proofs, also known as final proofs, simulate what the project will look like when printed, and once approved, become the standard for the press operator. Often, these proofs will be signed by the designer and or the client, and the person who does so takes responsibility for their quality and accuracy.

Off-press proofing systems are getting better all the time, but they are not perfect. It often remains difficult to accurately proof metallic inks, spot coatings or varnishes and fluorescent colors. It can also be difficult to predict the effect that colored or heavily textured stock can have on the appearance of the project.

As technology changes, so do proofing practices. But it is clear that soft, or monitor, proofing is the wave of the future. In the past, monitors could not be used for proofing, because they reproduce color differently than halftone printing. While monitors display images using the additive color process in red, green and blue (RGB) light, printing is produced using the subtractive color process, with cyan, magenta, yellow and black (CMYK) inks.

But now, with the help of special software, CMYK colors can be simulated on flat-panel displays. Printers, designers and their clients can calibrate their computers to produce virtually identical displays, and screen brightness can be controlled to simulate the brightness of the printed sheet. If a paper proof is required, users can calibrate desktop printing devices to match the printer’s press.

When the color is dialed in, the proofs are signed, and you are without questions, it is time to go to press. But that’s a story for another Ed—the next one, in fact (see Ed #11).

In the meantime, here are a few ways to make the prepress process go a little easier:

Design to avoid problems. While your creativity shouldn’t be limited by technical constraints, be aware that some design elements are difficult to get just right on press. Image crossovers in perfect bound publications need to be managed carefully—it’s next to impossible, for example, to reproduce a perfect circle that runs across the gutter. Type crossovers can be hard to manage in saddle-stitched books. Frames that run around an entire spread can also be hard to align perfectly.

Fix problems early. Some professionals talk about an informal rule of 10, where the price of making a change increases 10 times over at each step of the process. Adding a comma during preflighting is cheap and easy. Making the same change while the project is on press might cost thousands.

Pay attention to the type. With designers taking over the role once played by professional typesetters, something is often lost—thorough proofreading. Spell-check and grammar-check programs are far from infallible and no substitute for a trained eye. And don’t expect the writer to be the proofreader—they won’t see what’s on the page, only what’s in their imaginations.

Resolution counts. While modern prepress techniques can work wonders, they can’t do much to rescue a low resolution image captured with your cell phone camera. To successfully print a 150-line screen, the rule of thumb is that you should begin with resolution of at least 300 dpi, and higher screen rulings or stochastic printing might require a higher resolution. Ask your printer how you should send image files—in either RGB or CMYK. In the past, most printers wanted only CMYK files, but now some are requesting RGB files because they carry a larger color gamut.

And don’t forget the paper. While the prepress process is increasingly electronic, the end result still appears in ink on paper, and paper can have an enormous impact on the look and feel of the project.

Billerud delivers the right papers for virtually every project. Gloss allows you to print highly reflective art, such as photography, with wonderful clarity and sharpness of detail. Dull combines lower light reflection with better readability and uniform print smoothness. Glare-free, easy-to-read, matte has a rich, tactile feel that can help show high-gloss spot varnishes and coatings to advantage.

Prepress. Successful printing begins long before the job goes on press, with RIPping, trapping, preflighting, and a lot of questions.

Screen tests

Prepress planning includes determining the best screens for the particular project.


Check. Double check.

Preflighting ensures that the files the designer turns over to the printer will run properly in the printer’s systems and don’t contain any mistakes. Taking the time to preflight the project helps prevent problems later in the process, when they are far more difficult and expensive to fix.


The raw and the compressed

Most JPEG images are compressed by irretrievably discarding some of the information found in the raw image (right). Repeatedly resaving—and recompressing—the image causes even more information to be lost, hurting the quality of the image.


Bound to impress

Different binding techniques have different advantages—and often different layout requirements.

Saddle stitching is fast and inexpensive. In publications with high page counts, the thickness of the paper can result in page creep, which pushes type and images on the inner pages closer to the outer, trimmed edge.

Ring, plastic comb, spiral, and double loop wire bindings allow the publication to open flat, but except for ring binding, they cannot be printed on the spines. Inner margins must be wide enough to accommodate the binding, and crossover images will lose much of their impact.

Perfect bound publications are held together by a flexible adhesive. They are not as prone to page creep as saddle stitched publications, but text near the gutter can be hard to read. Depending on the weight of the paper, perfect binding requires a minimum of 16 to 20 pages.

Screw and post bindings accommodate large numbers of pages or heavy materials, such as wallpaper samples, and allow the contents to be changed easily.

Usually found only in hardcover books, sewn case bindings are the most durable and expensive.


A big imposition

Imposition places the individual pages on a press sheet so that the pages are in the proper order and oriented correctly when the sheet is folded, trimmed and bound. Imposition varies according to the number of pages and the type of press that is used.

As part of the imposition process the prepress technician will, if necessary, adjust for page creep, when the thickness of the bound paper causes the edges of each sheet to move outward. “Shingling” shifts the gutter or center margin of each spread slightly to maintain a consistent border after the pages are bound and trimmed.

1. Sheetwise imposition prints one side of the sheet with one plate then turns the sheet over and prints the other side using a new plate.

2. Work-and-turn imposition prints one side of a sheet of paper then turns it over from left to right and prints the second side using the same gripper and plates.

3. Work-and-tumble imposition prints one side of the sheet of paper then turns it over from the gripper back and prints the second side using a different gripper but the same plates.



4C B&W: Quadtones, or four-color “black and white” images made with four inks and printing plates, produce images of incredible richness and depth.

Two Hits Black: Presses with more than four printing units allow for the use of touchplates and spot and additional colors. Applying an extra or second hit of black ink can increase the contrast of the image.

Spot Me: Touchplates of Pantone colors 1375 and 300 provide additional color on a portion of the image.


Crossing over

Crossovers—running type or image across the gutter—creates a dramatic widescreen look but can be difficult to manage. It is especially difficult to match type, rules or circles. Crossovers also need to be adjusted to accommodate different types of bindings.



Image trapping slightly overlaps colors that adjoin one another to prevent the substrate from showing through if there is any misregistration on press. The amount of trap required varies according to the printing process and the paper.



Changing the proportion of cyan, magenta, yellow and black inks, shows that even relatively small changes in the mix can have a big impact on skin tones.


Small print

When type is printed from multiple colors, registration must be perfect or the type will lose definition and crispness. Tiny stochastic dots (left side) can help maintain legibility and sharpness of hairline rules and fine type.


Lose the gray

Gray component removal (GCR) can improve color saturation by replacing a portion of the three subtractive primaries with black ink. Like its cousin, undercolor removal (UCR), GCR can hurt the quality of the printed image if it is not used properly.


Some of the most common proofing technologies:


Proof it

The types of proofs you use will vary based on the type of job, the workflow—either analog or digital—and the progress of the project. Digital proofing methods are rapidly supplanting older, analog technologies.


Neatness counts

Standard proofreading marks make it easy for typesetters and editors to understand and make changes.