What is often a startling fact when first learning about color is the objects we see aren’t really composed of the colors we see. That green velvet chair you so love isn’t of itself really green. It has absorbed all the colors of our visible spectrum EXCEPT those that make up the green color. So how does that work?
A long-range view of the frequencies on the electromagnetic field of our universe shows that although we can pick up radio waves, x rays etc with various monitors, we can only “see” the colors in the visible light range in a field that occupies a space of 350 to 750 nanometers of space. A nanometer, remember, is one billionth of a meter! Translating that – we perceive color by our brains via our eyes in an electromagnetic field span of 1.37 to just under 3 inches! I don’t know about you, but I have a hard time wrapping my head around translating that miracle.
Einstein established that light is both a wave and a particle. This phenomenon became known as the wave-particle duality of nature – which defied any scientist’s ability at the time to describe. It has since led to the branch of science called quantum mechanics. Frequency is the number of waves per second (a wavelength being the peak of one wave to the peak of the next). Each color has its own frequency and length of a wave. Photons are the “particle” part of the phenomenon. Photons exude energy which excites our sense of sight but actually don’t have any mass in themselves.
As much as has been discovered about the intricacies of color science it is still difficult to comprehend that outside of our perception of color, it really doesn’t exist. Light doesn’t present itself as color. Light waves are colorless. What we perceive is a construction of how the brain interprets what the eye picks up in its very complicated mechanisms. Our eyes are constructed with about 7 million specialized cone cells within the retina of each eye. The cone cells allow for what we perceive as color. There are three different kinds of cones in humans (but rarely there can be four). The cones pick up light as a mere sensation, while the brain’s process filters and translates the information into something useful. Color from light is also picked up by rods in the retina. There are 100 million rod cells in an eye and are designed to perceive light in less bright environments. The rods function mainly along the outer sections of the retina and serve us best in peripheral and night vision.
The cones are specialized to pick up waves of a frequency as short medium and long lengths. Short waves make us translate as violet and blues. Medium waves denote greens and yellow to our brains. Long waves are interpreted as reds, yellows, and oranges. Two-thirds of the cone cells interpret long wavelengths resulting in humans seeing more variation in warmer colors than cooler ones.
What is constant in our understanding of color is that various wavelengths are emitted from the objects in our world. These mixtures of wavelengths are what we perceive as color. The chart below demonstrates printing ink colors on paper.
Wavelengths of light are picked up by the retinas’ components and carried by the optic nerve to be processed by the brain’s “departments” which adds detail and understanding. We can see why the retina is sometimes considered part of the brain.
Mosby’s Medical Dictionary, 8th edition. (2009)
So to understand a purple couch, the chemical combinations that constitute an object determines what wavelengths it absorbs and reflects. This corresponds to a frequency which corresponds to an energy level. The varying energy levels as well as the gaps in between correspond to varying wavelengths of light. The light is a result of the transfer of energy through matter which then is picked up by our retinas and put through an electrical/chemical process on a most minute level in our brain and voila we see a purple couch. Amazing!