Question

When all colors are absorbed, you see: white yellow green black

Answer 1

You see black, since none the wavelengths of light are being reflected back into the eye. Light is a prism, and the wavelength that is reflected is the color that you see.

Answer 2

Light and ink have different properties, so when you mix all lights together, you get white (hence Prism, Pink Floyd’s album cover) and mixing all inks together give you black.