CMYK - printing in color

A very good introduction to color. One assumption it makes will not always hold true. Many newer presses can print 6 to 8 colors in one pass. Thus you could do 4 color process and 4 spot colors with very little extra expense.

The biggest issue to understand with various color models is gamut. Draw a large circle. This represents all the possible visible colors. Next draw a square with all corners touching the circle. This represents all the colors you can produce with spot color inks. Next draw a trinangle with all corners touching the circle. this represents all of the colors you can produce with cmyk. Draw another circle about thre quarters the size of the first touching the first circle at one point. This is the RGB color gamut.

This is a simplified graphic and the actual color maps have much more irregular shapes but it highlights the point that there are colors you can produce using one model and not with others.