The primary colors of LIGHT are RED, GREEN, BLUE.
The primary colors of PIGMENTS/DYES are YELLOW, MAGENTA, CYAN (look at any business color printer -- you will find CMYK -- where K represents BLACK; photo color printers often add additional inks to produce a better gamut -- my ESP R2000 adds true red and orange; it's biased to producing accurate skin tones, others add half intensity cyan and magenta).
R&G light => yellow
G&B light => cyan
B&R light => magenta
Y&M pigment => red
M&C pigment => blue
C&Y pigment => green
Yes, thank you, I do understand that the artist's color wheel model of color theory is a tradition that does not correspond precisely to scientific definitions of how color works and how we perceive it. For printers, yes, the mix of basic inks is based on a different model. Got it.
My original post was not intended to create a debate on what the primary colors are (YRB, or YGB, or CMYK, or RBG), but rather, how much we may enjoy the colors of inks that fall in between whatever pure colors you choose as the starting point.
So do you have a favorite amber or vermilion or magenta fountain pen ink?
Edited by HalloweenHJB, 20 May 2020 - 21:26.