Totally different type of color v light models—transmitted light vs relected light.
Sum of all pigment colors is black absence of all is white.
Some of all light-based colors is white. Absence is black.
Although pigments in actuality fall far below the concept—all colors mixed is usually some muddy dark browny color.
BTW primary colors used in the printing process CMYK [cyan, magenta, yellow (and black or K)] actually are opposites of light-transmitted colors RGB [red, green, blue]. Cyan is opposite of red and contains green and blue. Magenta is opposite of green and contains red and blue, and yellow is opposite of blue and contains red and green—that last may be hard to swallow but try light through red and green gels and see what color it makes.