He's going by the primary colors of light, red, green and blue. The primary colors we usually think of are red blue and yellow, but those are pigment colors. White light has all the colors in it, while black is the absence of light. With pigments, like paint and stuff, Black has all the colors in it, and white is the absence of color.
If it helps, you can think about your computer monitor, its in RGB, while paper and stuff is printed in CMYK, cyan magenta yellow and black. :) 5/5
 "Colourshift"){kind=icon}
 "Music Catch 2"){kind=icon}
 "Music Catch"){kind=icon}