Colors are thus an optical illusion, what we see are reflected photons (light) from objects in some particular frequency ranges. Examples: red (405 to 480 Thz), yellow (510 to 530 Thz), blue (620 to 680 Thz), violet (680 to 790 Thz), wavelength and frequency possess inverse relationship, i.e. the shorter the wavelength, the higher the frequency. Black is actually not even a color, but the absence of color (no or little reflected light). Black materials are materials that absorb all wavelengths of visible light. So if it absorbs everything, we don't get anything reflected back to us, then we see an absence of color: dark. On the other hand, a white wall is all colors but white, as we see "white" because that's the frequency it reflects (reflected light and frequency) to our retina.
Morpheus in "The Matrix" said: What is real? How do you define what is real? If you're talking about what can be smelled, tasted and seen, then real is simply an electrical signal interpreted by your brain.
