PRINTING 101, Color Modes
In illustration and printing there are only a few basic forms of color.

RGB
The first mode is RGB, or Red, Green, and Blue Light. This is the color system your television and computer monitor uses, combining the three colors to produce a range of colors. RGB can also refer to inks in a simple inkjet printer and sometimes it is the print mode you'll select when printing to your inkjet even if you have a 4 color ink cartridge sytem. RGB is not typically used in commercial printing, but I have seen it done with varying results. Some sophisticated digital printing systems may use RGB, but when putting a color print job on a press, they'll most likely use an ink system called CMYK.

Tip: Using RGB instead of CMYK is not a good method of reducing printing costs.

CMYK or Four color or process printing
CMYK is a four color ink sytem, C= Cyan(Blue), M=Magenta (Red), Y=Yellow, and K= Black, CMYK is also called process printing, because there are 4 process' in the printing,adding each color is one process. Remember your first grade art class where you learned to mix red and yellow to get orange? That is basicallly how CMYK works, mix portions of any of the four inks together and you get the desired color.

SPOT COLORS
There is also a system called Spot Colors. Spot coloring uses from one to three colors (or more in some industries) with out mixing them together, for example a black circle, with a yellow filling, and a blue star in the yellow filling… like a logo. Most silkscreened t-shirts are done with spot colors.

Tip: Unless you REALLY need to use full color illustrations, consider using black line art with a spot color. Black with 2 spot colors might even be a good option, but you may still be looking at the job being printed on a four color press.

So, what does all this mean when you're dealing with an illustrator or printer?
Well, the color mode you want to use is one of the first things we'll want to know. It will determine your production time, process, which printing press is used, but will impact your book production cost more than any other element.

As an illustrator, I would not typicaly make an RGB illustration unless it was for digital use, such as on the internet or if you plan to print the book digitally. So the two options which would determine my price would be, is it a cmyk four color process illustration, or is it a black art with some spot colors? There are some other minor differences in each of the color modes, and the techniques used to produce each. To learn more about that and see visual examples, go to colors compared.