Answered by Stephen Beals, Digital Pre Press Manager and Writer

Question:
I would like to get some information on four color printing of black/white photography within brochures/booklets. As an Art Director, what do I need to be aware of when designing such a piece? Also, where can I locate some printed samples to share with my client? Thanks!

J.H.

Answer:
There are pluses and minuses to printing black and white photos in 4/c process, so we'll look at the minuses first. We're sure you have already considered the biggest minus: the three extra plates it takes to print process color. But there are other issues. The registration on process color is obviously more critical, and mis-registration may be more noticeable since the out of register color would contrast with the neutral image. But the biggest problem with printing black and white images with process inks is that it is very easy for the finished photo to have a color "cast."

Neutral grays are the most difficult colors to print on press, so they might drift a bit and take on a "red" (warm) or "blue" (cool) color cast rather than a perfectly neutral gray. One way to avoid this is to opt for an intentional "cool" or "warm" cast. Some designers like to play with different color casts within a piece to give a unique look to the finished piece. If you want to stay with neutral black, you should opt for greater GCR (gray component replacement) when the images are scanned. Essentially it means you will be printing more black ink and less of the other three colors, but still get the enhancement effect of the process inks. It's a trick to give the press operator a bit more control over color cast.

One last issue: a four color image can show a screen pattern (moire) particularly if there are textures in the image (like a herringbone suit coat). These can show up a bit more in black and white process than in a standard process color separation. With most printing systems today, that should not be a major concern.

The biggest plus is ink density. The images have more "snap" when printed in process color because there is more contrast. You can simply have more ink coverage with four inks than you can with one. You'll see a greater difference on a coated sheet. You also have greater control over the amount of detail you can hold on press.

Your paper specification rep or printers are good resources for samples of four color black and white printing.

Stephen Beals is a digital pre-press manager and has been writing for major print publications for many years. He is the author of A Practical Primer for Painless Print Production. He can be reached at stephenbeals@mac.com.

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