How Famous OS Logos Got Started
Shane O'Neill writes "Ronald McDonald and the NBC Peacock may get more TV air time, but today's operating systems have cool logos, too. Google, Apple, Microsoft and the Linux crowd crafted mascots ranging from cute lizards to circles of life. In this slideshow, we look at the origins of the logos and look ahead to their future."
Don't bother with the 'article'. It has no insights into any of the logos and is merely idle speculation on the part of the author for the most part.
You have been warned. . .
There are no magic three color pigments that actually exist to make all other colors. red, blue and yellow as the 'mother' colors is just a construct. as far as those TV's are concerned, using the subtractive method (light, not pigment), Red Green Blue ARE the primary colors, because it uses them to make all others it can. Read up on trichromats. You can use lots of 3 different colors as the primary colors.
Whatever you get, you wouldn't get four colors.
If you want to get really technical, Red, Green and Blue are the additive synthesis primary colours, and Yellow, Cyan and Magenta are the subtractive synthesis primary colours.
Yes, the Black component can't be called 'B' because of Blue. It gets the 'K' because in printing it's often called the Key colour. (and the added bonus of having that letter in its name)