Digital prepress, the conversion of electronic information about text and graphics into output-ready form, is a crucial aspect of book manufacturing.
But it takes more than looking good on a computer screen for titles to translate from bytes to ink on paper.
When things go well, prepress production reflects modern technology at its best. But incorrectly prepared electronic files wreak production havoc, and are the top cause of production delays, surcharges, and missed delivery dates.
Here are the most common causes of prepress problems, as nominated by a team of technical experts at R.R. Donnelley, in New York.
If your organization hasn't been tripped up by these common blunders, congratulations. Give your team a collective pat on the back.
If, however, this list strikes close to home, it's a good idea to build your organization's prepress skills through seminars and training sessions.
PDF (Portable Document Format) boosted the prepress workflow, and is preferred by many printers. Because PDFs require embedding of images and fonts, many believe any PDF file is a perfect package.
That's not the case. It's devilishly easy to make a bad PDF. Fonts can be incorrectly embedded, images can be at the wrong resolution, output can be misdirected.
To avoid the pain of rejected files, contact your prepress provider about settings and requirements before distilling your PDF files.
Printers are eager to share their preferences for font embedding, trapping options, and printer settings.
A layout won't look the same on a computer that doesn't have exactly the same fonts installed as the computer on which it was created.
Even an identically named font from a type foundry can have multiple versions, each with miniscule differences that can spark document reflow.
Add to that subtle tweaking that designers might apply to a font, and you have the potential for prepress disasters.
To ensure proper output, always supply your printer with the exact screen and printer fonts used in application documents—and be sure to include them all.
Transferring font files is completely legal, provided the printer maintains valid licenses to the associated font libraries.
Here at R.R. Donnelley, when a job uses a typeface we don't own, we purchase the font from the foundry as a standard procedure.
Cameras and computer monitors capture images using the colors of light: Red, Green, and Blue (referred to as RGB).
But four-color offset lithography is based on an entirely different system: The Cyan-Magenta-Yellow-Black (CMYK) color system.
Proper file preparation includes translation of all images from RGB to CMYK before sending them to the printer.
Failure to make this translation early in the workflow can trip you up. You've put time, effort, and squinting into the color correcting of RGB images, but they're not in their final CMYK format.
Additional processing will be needed on the prepress end to translate all the images from RGB to CMYK. Worse, the proofs you get back will show color that differs from what you expected.
Many publishers streamline the production of application files by using Open Prepress Interface (OPI) to simplify handling of high-resolution scans.
With OPI, two versions of each image are generated at scanning. The smaller, lower resolution, faster rendering file is used by the designers to create the digital layout.
The larger, higher resolution image remains in the scanner's system until production begins. During processing, the lower-res image is automatically and precisely replaced by its higher-res sister, balancing optimum digital quality with processing efficiency.
The key to this approach is in the parallel naming of the files. The computer comprehends the common naming conventions, and swaps the images with precision.
Changing a file's name will break these links, potentially substituting the wrong image, and bringing prepress processing to a screeching halt. Therefore, never, ever rename lower-res versions of OPI-linked files.
The prepress process slows to a crawl when the printer receives an envelope with a disk-and only a disk-inside.
Omit an explanatory cover letter, or send the wrong version of a hard copy, and the door to job miscommunication is opened.
Accurate proofs must accompany and identify pages submitted on disk for processing. This simple clerical step assures proper image placement, allows page count checks and blank page placement, and keeps the printer in sync with your purchase order.
Always take the extra minute to confirm the hard copy you send for production is identical to the file on disk.
Production stops and schedules are blown when a discrepancy is discovered between supplied copy and output proofs. Worse, errors missed due to mismatched proofs can make it to press and out to readers.
Here's a recipe for output disaster: Set some type, and save it as EPS1. Import EPS1 into Adobe Illustrator, and make it part of a logo. Now save the art as EPS2, and import EPS2 into a QuarkXPress page.
Buzz! You lose! Nesting files inside other files demands intricate processing that confuses a RIP. The result can be substituted fonts, reflowed type, and gaping holes in your output.
Nesting files also creates linking problems between applications that causes unpredictable results.
Avoid nesting by converting type to outline form in a drawing program before importing it into the final layout document.
Keep a copy of your original type file, in case later corrections are necessary, as outline-format type isn't easily corrected.
The computer revolution notwithstanding, the human element remains a big part of the prepress equation.
Often a prepress operator will spot something in a layout that just doesn't seem right. Rather than proceeding to output, processing is put on hold until the designer's intent is determined.
Unfortunately, responses can be hard to come by when messages aren't returned for hours or days. To assure smooth prepress sailing, make certain that designers are readily available during the production phase.
Keep customer service reps informed of the designer's whereabouts while files are being processed. Appoint a contact person when the key players will be out of reach.
Nobody wants a book with type hanging off the page, or images sucked into the gutter. Yet prepress production is frequently stopped because pages are designed with live matter too close to the trim.
Speak to your printer's customer service rep early in the design process of a title to avoid these delays. Review the requirements for a book that uses your binding style, and follow the minimum safety margins for non-bleeding illustrations or type.
Proper file preparation is of the utmost importance when a page is designed to bleed. Prepress processing can be slowed when layouts neglect to include extra image or tint areas extending beyond the page's crop marks.
Bleed images must extend 1/8" past the final dimensions of a book to ensure no white space shows when the text block is printed and trimmed.
Conversely, if illustrations or type are not meant to bleed, there must be a minimum safety margin on all sides of the pages, varying with the binding style of the title.
Colors designed to fit together tightly can shift on press. Files must be trapped (prepared so adjoining colors overlap slightly) to avoid gaps between adjacent colors.
Determining the correct overprint or underprint for abutting color elements is tricky. Every project has slightly different trapping needs, and every press requires unique consideration.
Though major printers now utilize systems that handle trapping, your pages might contain elements that require additional attention.
Incorrect traps add time and money to the production cycle, so discuss trapping with your printer early in a title's production, preferably during the design phase.
After-design trapping requires complicated and pricey "reverse design" of pages to analyze document structure, and trap elements accurately.
The simplest way to assure smooth prepress production is to avoid panic situations by planning ahead.
Work with your printer to develop a schedule that meets your needs, and stick to it! Allow enough time for file testing, plan on an unhurried review of proofs, and build in adequate opportunities for editorial revisions.
The time you spend organizing and reviewing your projects up front will reap big rewards during production, on press, and beyond.
Marcia Lerner is a manager of solutions development for R.R. Donnelley's
Book Publishing Services Solutions, in New York. Her responsibilities
include project management, workflow analysis, and communications that
support the publishing arts. She has twenty-five years of industry