The printing press has been around since the days of Gutenberg, and the printing industry has developed a terminology that sounds like a foreign language to anyone unfamiliar with it.
As a desktop publisher, it’s a good idea to be familiar with some of the terms that your printer may use when discussing a print job with you. While it would be impossible to go into too much depth in a short article about the printing process, the following is a quick primer on some commonly used terminology in the printing business.
Bleed – In a perfect world, when a printer trimmed your job, it would be cut exactly along the crop marks specified. While technology has made the world a better place, it still isn’t perfect; trimmed documents can be off by as much as 1/8 of an inch at times. To compensate for this, printers will ask you to bleed page elements off of your document area, in order to allow for slight imperfections in their trimming.
Overprint – When you print an element over a previously printed element on a document, this is called overprinting. A good example would be text printed on a shaded, colored box. If the text is black and the screened box is a light color, this works fine. If your type is a light color and the screen is a darker shade of a different color, it can be a disaster. Talk to your printer ahead of time to ensure that this isn’t a problem.
Overrun – This is different from an overprint. Since there is always some wastage in the offset printing process, a printer almost never runs exactly the number of copies that you request. Usually, to compensate for wastage, a printer will aim for an overrun, giving you a few extra copies. Of course, sometimes the wastage is more excessive than planned, and you end up with a few less than expected. This is why many printers will stipulate in their quote that the run will be within 10 percent over or under the requested amount (that’s an arbitrary figure; different printers might specify more or less). Take this into account when you are planning a job.
Saddle stitch – If you only deal with single sheet documents (say folded brochures or single page newsletters), don’t worry about this term. If you have a multipage document that needs to be folded and then stapled along the spine, then knowing that you need it to be saddle stitched will help in your communications with your printer.
Trapping – Again, as already noted, we don’t always live in a perfect world (especially when it comes to printing). When you are printing a multi-color document on a printing press, separate plates are used for each color. If those plates line up perfectly, adjacent colors will meet perfectly and your printed piece will look exactly as it should. In the real world, however, plates are not always perfectly registered, and the result can be white space between adjacent colors, where there should be no white space. The solution is trapping, where there is a slight overlapping of colors to compensate for this. If you don’t know how to do this in your page layout software, talk to your printer ahead of time, because trapping can be a minefield for the beginning desktop publisher (and even experienced graphics professionals).