RGB versus CMYK:

What you see isn't always what you get. It is very rare that a computer monitor will accurately display 'true' color and this one of the most frustrating aspects of printing for inexperienced and experienced designers alike. Professionals often spend several thousand dollars, and expend a great deal of time and effort to calibrate their systems so the images displayed on their monitors will be as true to the actual color values they have chosen as possible.

Red, Green, and Blue are "additive colors". If we combine red, green and blue light you will get white light (as seen on the 'additive' illustration noted above). This is the principle that television sets operate on as well as the computer monitor you are staring at right now.

Cyan, Magenta and Yellow are "subtractive colors". If we print cyan, magenta and yellow inks on white paper, they absorb the light shining on the page. Since our eyes receive no reflected light from the paper, we perceive black... in a perfect world!

In practice, printing subtractive inks may contain impurities that prevent them from absorbing light perfectly. They do a pretty good job with light colors, but when we add them all together, they produce a murky brown rather than black. In order to get decent dark colors, black ink is added in increasing proportions, as the color gets darker and darker. This is the "K" or "key" component in CMYK printing (the "K" stands for "Black"). 

Additive color (RGB color mode) is optimized for display on televisions, computer monitors, scanners, etc. Digital cameras also use the RGB color mode. The commercial printing world operates in subtractive color, or CMYK mode.

Whoops!
 
One of the most common errors made by inexperienced graphic designers is submitting RGB files for CMYK print. As a result the RGB images must be converted to CMYK before we send the files for film output or to print. In most instances there isn't a great deal of color change, however, sometimes the color range gets compressed during its transition to CMYK mode. The result is that some colors may change. Be warned that there is no wa to get that deep/vibrant RGB blue using CMYK, no matter how much we may want to.

The Pantone Corporation has gone to the trouble of standardizing CMYK color and how it should appear on paper. One book they sell is called PANTONE® process guide coated SWOP.

This gives the designer the ability to see the printed results of the CMYK % values they set in their program's color setting.

Since CDman uses 100# Gloss Text paper stock we use the Coated paper ("C") color selections as opposed to Uncoated ("U") color selections when trying to decide on CMYK values.

If we refer to a Pantone SWOP book and not our monitors or anyone else's, we will get a much more accurate impression of the 'true' color... despite what our computer monitor tells us. Obviously no book can contain every tint possible and each offset press is slightly different, but there will be a whole lot fewer surprised people if guide books are used.

Terms in brief:

Process = CMYK (mixing 4 primary colors together)

SPOT color = Formula to obtain one 'spot' shade.

Pantone Swatch Book Suffixes:

C = coated paper

U = uncoated paper

CV = computer video

CVC = computer video simulating coated paper

CVU = computer video simulating uncoated paper