More on Trapping

A colleague recently used a gang printer with some of the best prices on the planet for 4/4 postcards. Beware of these guys who offer the best prices on the planet, and I’m going to tell you why. There was a lot of rich black, rich black is four colors touching top to bottom, trapping is a good idea when using rich black.

If you are unsure how to set up rich black, or trapping, talk to your friendly pre-press technician. Speaking of friendly pre-press technicians, these so called gang printers are supposed to have pre-press technicians. Sandee wrote a good article on trapping, if you are unsure what trapping is, or why it is needed, see the article, or refer to “From Design into Print,” the book.

Back to the postcard, one side had heavy goldenrod and black coverage, using Copperplate Bold. The mail side had an image in the upper left corner, and left the required room for the Post Office to put bar codes and met the requirements set down by the post office. My colleague called the gang printer, and asked about trapping. “If you want trapping, that is something you will have to set up.” So she did. She sent in the file, and when the samples arrived, trapping had been ignored. The small serifs on Copperplate Bold were only hints of what there should have been. The text over the photo, Myriad, looked somewhat skeletal. When the file was printed to a postscript file, with trapping turned on, the black separation fell to the bottom. From Acrobat, Advanced > Print Production > Output Preview, check simulate overprint, and the black showed up as trapped.

She said her customer did not notice when he saw one of the samples. She cringed, knowing she saw something he did not. The best price on the planet means nothing, if the shop can not or will not apply trap. She talked to the gang printer before the file went to press about the trapping. Each time, she was assured that the file would be ok.

When you hear, “We don’t trap, we just print,” run. I would also suggest, that if you are sending in multiple orders, and the gang printer in question can not offer combined shipping, run. Most gang printers will send out samples upon request. When you get the samples, get out the loupe and look closely at the rich black samples. You should be able to see if the file trapped.

Disclaimer: Not all gang printers ignore trap. As a designer, if you are going to use one of these gang printers with the best prices on the planet, talk to them. Ask questions. Not everyone ignores trap. There are gang printers that will tell you not to worry about trap, they will take care of it, and they do. Do advise them, when you send in a file.

Here are links to two files, one has trapping, one does not. PJ.SampleTrap01 traps the black text to the yellow background. When overprint preview is turned off under the Advanced menu, or on the Output Preview dialog box in Acro 9, the yellow fills in around the black letter. PJ.SampleTrap02 does not have trapping and the character looks like it is supposed to. With the second file sent off to a gang printer that does not trap files, there could be a slight misregistration of CMY plates, and a halo will appear on one side of the letter. Just because there is CMY in the black formula, and MY in the yellow background, trapping is still a good solution to make the print job a success. A slight misregistration of all plates is possible, giving a rainbow halo around the character. Feel free to download the files and check them out.

1 Comment »

  1. bharrel Said,

    July 28, 2009 @ 8:02 pm

    I wouldn’t think of using a printer or service bureau that didn’t check to see that the file was setup right.

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