Harald,
I went through this about 3 years ago. The biggest problem in color accuracy is
matching the gamma factors among screen display, original, and printout. If you
set the gamma factor to 1.0 for each color, the chances are pretty good that
you will have accurately reproduced images. I'm colorblind, I own a set of
Ishihara's plates, and my reproductions are accurate. These are also a good
ice-breaker at parties.
Micrografix and Adobe's PhotoDeluxe are good programs, because they let you
control the gamma factor.
I might also suggest a text "Color in Business, Science and Industry" by Judd
and Wyszecki. The text is a bit dated, but right on the money when it comes to
color reproduction.
Thomas Jakubowski
Naperville, IL