A graphic design lesson I learned years ago is that printing is a less-than-exact process. That means that even if you design your project “perfectly”, you can run into problems if you don’t keep important text and visuals away from the edges of your piece. If not, words get cut off, thin borders will look uneven and photos may be cropped in a way you don’t want.
Why printing is not always perfect
Nearly every job I’ve had printed in my career has been on an offset “sheet-fed” press. That means each sheet of paper is run through individually. The are a few reasons sheet-fed printing can be imperfect. One is because of an effect called “rattle”, meaning that each sheet can be “pulled” through the press slightly askew from the sheet before and the one after. That means the printed image may be in slightly different position on the paper.
Another reason for imperfect printing is that when the sheets are cut into a final size, each cut may be slightly different. That can cause things like borders to be uneven or text to be cut off.
A third problem can happen with folding or die-cutting into special shapes. Although these are done with machines, the sheet-fed process can cause rattle as well. That can also leave things cut off and uneven.
You often won’t know how a job will be printed
Another graphic designer’s challenge I’ve discovered is that clients often are unsure of how the materials will be used. They won’t know in the beginning whether the piece will be an offset printed document, or only distributed by email or on the web. That’s another great reason to keep your important visuals and information away from the edge. When documents are distributed as PDF files, you lack control over how the piece will be printed. It requires that you assume it will be on a standard printer and a letter-size sheet with a white edge around the printing, since you don’t know where the “gripper” edge will be. (Gripper is the term for the non-printing edge of the paper that gets “pulled” through the printer.)
Safety in fractions
To solve this printing design problem, we often begin designing with a 3/8″ to 1/2″ border as a “safe-area” for important text and graphics. Then if we choose to bleed the ink off the edge when the piece is offset printed, we will add border elements—bleeding background images, lines, or designs—as a layer in the file. The layer can be turned on for output to offset printing, or turned off when creating PDFs for digital sharing.
One last point about this “rule”—as a designer I believe that the rules are sometimes made to be broken. Just break them well.