The document discusses the chemistry of paint making and color perception. It explains that light hits the eyes and is focused on the retina, where rod and cone cells absorb light and send signals to the brain to perceive color. Making paint can be difficult as it requires finding chemicals that produce the desired color when reacted. An example reaction is provided to make blue paint by adding iron(II) sulfate and potassium hexacyanoferrate(III) solutions dropwise. The colored solid is then separated, ground, and mixed with oil to create paint. The energy from chemical reactions produces the wavelengths of light, and therefore the colors, that we see.