On Monday, we outlined steps to take during the creation of your file to ensure the final printed output looks as expected. Today we’ll talk about other steps in the production process that you should keep in mind. Before a PDF file can be used for printing, it must go through a process called preflight. There are two parts to preflight, Content preflight and Technical preflight.
Content preflight, completed by the customer, confirms that all necessary components of the file are present,
including placed graphic images, fonts, bleeds, and correct color assignment. Content preflight also includes spellcheck and proofing.
Technical preflight, completed by the printer, examines how the file is constructed and assesses whether it is ready for raster image processing – converting fonts, line art and photographs into dots. During technical preflight, we check image resolution, colors, allowance for bleeds, trapping values, trim and paper sizes. We also impose multi-page documents into printer spreads so that pages will back up correctly, or put more than one image on a page when the finished size is less than the size of the press sheet.
Technical preflight may reveal problems with the file that will compromise quality or prevent raster image processing. We’ll let you know if the file passed preflight and has been scheduled for printing, or if we uncovered a problem. If there’s an easy fix, we’ll give you the cost of repair so you can approve, or you can ask to have the file returned so you can fix it yourself.
Please be aware that there are some problems that we consider “fatal flaws” that we’ll always ask that you repair before resubmitting the file. One example of a “fatal flaw” would be the lack of the 0.125″ allowance for images that bleed, or low resolution images. It is very helpful if when submitting a PDF file you let us know anything that intentionally deviates from standards, like a low-resolution, pixelated image included for artistic effect, so we will not count this as a fatal flaw.
Allowing for finishing operations
Some documents, like brochures or booklets, require additional work after printing that must be taken into account during file preparation. Here are the allowances for folding, drilling and booklet binding.
To produce a completely flat and even fold, the size of panels that fold in must be slightly smaller. To compute the adjustment mathematically, determine the width of single panel if all were the same size, reduce the width of the panel that folds in by at least one-eighth inch (or more, depending on the thickness of the paper being used for the job), divide by two and add that amount to each of the outside panels. In addition, the position of the inside panel changes from the front to the reverse.
When the finished product requires holes, allowance needs to be made in the margins. We recommend a half inch clear space an 8.5 x 11″ sheet, so shift the margin to the right for one-sided pages. For two-sided pages, shift right for odd-numbered and left for even-numbered pages.
Booklets require special consideration during the design process. The live print area for a booklet should be 0.25″ of white space on all sides of the page. Keeping text and artwork within this live area is critical. Booklets consisting of more than two or three flat press sheets folded into a booklet are subject to shingling – the effect of having each folded signature (i.e., multiple finished pages on a press sheet) wrapping around all previous signatures. After binding, the opposite edge is trimmed to produce an even edge. Without an allowance for this trim, it is possible that text, page numbers or other images may be trimmed away.