Why do you get white light when you mix all colors of spectrum, but black when you mix all colors of matter?

Answer 1

Because the coloured lights are additive, in other words they radiate the colours so they combine to make white.

Coloured paints are subtractive, they adsorb the colours they dont reflect so if you have matterials that adsorb all the colours then you have nothing left to reflect and so get black.

Answer 2

You do not mix.

In the first case you add the light of different colored light sources.
Add all the colors together = white light.

In the second case you have a white object painted in one translucent color (assume red) Now the green color of the white light get absorbed and all colors except red get attenuated. So you have subtracted some colors.

Now you add a second layer of translucent color (assume blue) Now this second layer absorbs mostly the yellow colors and attenuates all the other colors except blue. The object will now appear violet-magenta.

Now you add a third layer of translucent color (green) Now this third layer absorbs mostly the red and magenta colors and attenuates all the other colors except green. Note: green was absorbed by the combination of the first and second layer. The object will now appear black. Because all the colors are absorbed (subtracted)

Answer 3

pure white is a mixture of all colours in equal proportions

Black is NOT a specific physical colour. It is the ^physiological colour (visual sensation) that you feel than an object does not diffuse any colour!

Answer 4

I get a dirty brown every time - have you ever actually tried this?