Black is all pigments. It is the absence of color.
If I'm not mistaken, I believe you have to make a distinction between black and white under two different circumstances: a.) printing and b.) light.
Your description is correct, I believe, for printing.
But with light, it is contrary: white is all colors (see prism and associated spectrum), while black is the absence of light (thus, any colors).
Black is all pigments. It is the absence of color.
Yup. But light is the complete opposite as pigment. Add all colors together to get white. Remove all light and you get black.
When I was young, that confused me a bit.
You can truthfully say that light is both the presense of all colors and the absence of all colors. Just depends upon what you are talking about.