Here's something a friend of mine and I made in our spare time.
It uses a pic (doesn't really matter which one) to drive two 4017's (multiplexers) and four 595's (colour drivers). This is just an example of what it displays.
It was impossible to put all 4 next to each other on the breadboard.
Light is an additive pallet not a subtractive one, R+G==Y
CYMK is Cyan Yellow, Magenta, Black. These are from an ADDITIVE pallet.
Black is used in colour printers because the best black pigments are WAY better than the best CYM pigments together.
i'm a copier technician and if i remember correctly, the YMCK is a SUBTRACTIVE color model(for toners, etc.) whereas RGB is an ADDITIVE color model(lights, etc.) and the RYB is another set of subtractive primaries(primarily for painting). i may be wrong with the RYB model, but i'm pretty sure about the YMCK and RGB