How to Achieve Great Color Every Time (1,549 words)
Catalogers also have responsibilities within this partnership. For example, they must provide color proofs to ensure that these proofs are an accurate representation of how the job is likely to print. This presumes the customer is familiar with color web offset printing and its limitations; there are limits to the colors that can reproduce on a press. And the cataloger must be aware that their choice of paper has a major effect on the appearance of the finished job.
"That orange looks dull. Fix it!": The Basic Principles of Color Reproduction
Every device that perceives or reproduces color has a built-in "color space." This is the range of colors that the particular device can reproduce. The most important device is the human eye, because any "color" outside human perception is irrelevant. Where print jobs get into trouble is in the difference between the color space of the art director's computer monitor and that of the printing press.
A computer monitor is an "RGB" device. It reproduces color using dots of red, green and blue. The color space of a monitor is smaller than that of the human eye.
Because printed color is reflected off the paper, it is created by either absorbing or reflecting color, not by projecting light, as the monitor does. Printing presses therefore use the complementary colors of RGB, which are cyan, magenta and yellow. The CMYK color space is even smaller than the RGB. In other words, just because you can see a color on the monitor doesn't mean you can have it on press.
The cataloger's best tool for ensuring that the desired color comes off the press is a good color proof—a full-color representation of the page to be used on press to predict what the final printed page will look like. We say "predict" because there will always be differences. The proof is being printed on a device that also has its own color space, and this space, or "gamut," is much larger than that of a printing press. It is also printed on a substrate that may or may not resemble the paper on which the job is to be printed. The paper you use on press has a big effect on your color space.