Epson Stylus Scan 2000 User Manual page 196

Note:
In theory, pure cyan, magenta, and yellow should produce black, but
actually they produce a muddy brown and must be combined with black
ink to produce a true black (K).
Your monitor produces images by illuminating color phosphors
on the screen with an electron gun. (A phosphor is a substance
that gives off light when irradiated.) Each screen point (pixel) has
three colored phosphors: red (R), green (G), and blue (B).
Since the printer and monitor produce color images differently,
and the available range of color produced by the monitor and
printer are different, the image on the screen does not exactly
match your printed output all of the time. If you want to adjust,
or calibrate, the printed color to more closely match the on-screen
color, you may have to experiment with the printer driver
settings.
Additionally, color management software is available from a
variety of software and monitor companies to help you match
colors produced by your monitor and printer. See your image-
editing software documentation for information on color
matching.
monitor colors printer colors
The range of colors that can be displayed:
A-3
Tips for Color Printing