Color Blending - first of all, let's wonder what we're talking about: pigments or colored lights?
The purpose of mixing two colors is mainly to get a third one; quickly, one wondered which colors
and how many could possibly give the most extensive palette.
That simple "everyday life" problem led practitioners and theorists very far; here is some of their investigations' results:
CMY set - Cyan, Magenta, Yellow
It appeared that a set of 3 colors is enough to get a usefull palette,
providing you know if you deal with pigments (as in painting) or colored lights (as on screens) because the primary colors must be different for each set;
pigments blending as above is subtractive, which means the CMY mix tends towards black - more theoretically than pratically though,
that's why printers use a CMYK set where K = blacK
Colored lights blending tends towards white; 3 searchlights, Red, Blue & Green, pointing to the same spot would give a white surface. Primaries and secondaries
switch places. One can see that what is added or substracted is the light.
CMYK chromatic cercle; blend 2 colors, then the resulting mix, then again: you get a real palette
printing patterns - CMYK, paper color acting as white - use an optical blending: you cannot see the
Cyan, Magenta, Yellow & blacK dots but a mix of reflected lights.
The size of these patterns (weft) fits what you're printing on: books, posters...
and it is orientated to get rid of the moiré
- sample is zoomed in.
Top right, inkjet patterns are digitally computed, beeing therefore more complex & random