CSS black or white -- colour vs shades??

Question

Why black or white are not considered as colour and just the shades in CSS design or in general thought?

Answer 1

Black is absence of light and it is light which allows us to see colour. When all the colours are equal, that makes white.

Answer 2

let me give some comments about this topic:

> in the additive color system (RGB, which is used in screens), only when all three colors—red, green, and blue—are at their maximum value (255) we get white.

> however, if the values are the *same* but not the maximum, such as 128, 128, 128 we get a shade of gray, because gray is a balanced combination of red, green, and blue at lower intensities.

>>
255, 255, 255 = white (maximum intensity of all colors)
128, 128, 128 = gray (equal but lower intensity of all colors)
any other combination where R, G, and B values are equal will give various shades of
gray, depending on the intensity level.