Color Doesn't Exist Without Light.
The subtitle for this page should probably be, “do you remember Physics 101?” Color would not be possible without light; in fact, color is light—either viewed directly from a light source or reflected from objects that we see.
No; color is a perception created by our visual systems in response to light. No light, no perception of color.
So without light, there is no color. However, objects still retain their characteristics. A blue shirt still has all the properties to reflect blue light and absorb the other colors, even in the dark.
Not only can color exist without light, it always exists without light. Color is produced by your brain, full stop. It is produced by brain tissue. It is not a property of light.
We only see the light waves that are reflected off of the object! So if you think someone is wearing a red hat, they are actually wearing a hat that is completely colorless. But when light hits it, every part of the color spectrum soaks into the hat except for red, so that's the color you see.
Colour is not a physical property of an object - it is a sensation, just like smell or taste. Colour is generated only when light of a particular wavelength falls onto the retina of the eye and specialized sensory cells generate a nerve impulse, which is routed to the brain where it is perceived as being colour.
It only exists in your head. Bevil Conway, a neuroscientist who studies color and vision at Wellesley College, explained it this way: “Color is this computation that our brains make that enables us to extract meaning from the world.”
Magenta doesn't exist because it has no wavelength; there's no place for it on the spectrum. The only reason we see it is because our brain doesn't like having green (magenta's complement) between purple and red, so it substitutes a new thing.
So why is that? Part of the reason is that there isn't really a true blue colour or pigment in nature and both plants and animals have to perform tricks of the light to appear blue. For plants, blue is achieved by mixing naturally occurring pigments, very much as an artist would mix colours.
Rods are highly sensitive and work well in dim light, but they can quickly become saturated with light and stop responding. They don't sense color, which is why we rarely see colors in dim light. Cones, on the other hand, allow us to see colors and can adapt quickly to stark changes in light intensity.
About 8% to 10% of the male population is colorblind. Colorblindness is most present in males due to the way genetics work (see footnotes). Only an estimated 0.5% of the female population is colorblind. Tritan-type colorblindness is not gender specific, women and men are equally affected.
SUMMARY. The dual retina of humans and most vertebrates consists of multiple types of cone for colour vision in bright light and one single type of rod, leaving these animals colour-blind at night.
There are an infinite number of fundamental colors, if by "fundamental" you mean "spectral". Spectral colors are also known loosely as rainbow colors. A spectral color is composed of a single fundamental color on the visible part of the electromagnetic spectrum, as opposed to a mixture of colors.
First, no two colors can be mixed to create a primary color. In other words, primary colors can only be created through the use of natural pigments. Secondly, all other colors found on the color wheel can be created by mixing primary colors together. The secondary colors are orange, green, and purple.
If colours were simply a naming scheme for wavelengths then pink is not one, because it is made up of more than one wavelength (it's actually a mix of red and purple light). If you took a laser and tuned it across the visible wavelengths, from infrared through to ultraviolet, you would not pass pink on the way.
The first thing to remember is that colour does not actually exist… at least not in any literal sense. Apples and fire engines are not red, the sky and sea are not blue, and no person is objectively "black" or "white". What exists is light. Light is real.
Colour is an illusion, not part of the real world
“Every colour that people see is actually inside their head … and the stimulus of colour, of course, is light.” As light pours down on us from the sun, or from a lightbulb in our home, objects and surfaces absorb some wavelengths of light and reflect others.
Light receptors within the eye transmit messages to the brain, which produces the familiar sensations of color. Newton observed that color is not inherent in objects. Rather, the surface of an object reflects some colors and absorbs all the others. We perceive only the reflected colors.
Light is made up of wavelengths of light, and each wavelength is a particular colour. The colour we see is a result of which wavelengths are reflected back to our eyes. The visible spectrum showing the wavelengths of each of the component colours. The spectrum ranges from dark red at 700 nm to violet at 400 nm.
By definition, a theory is not a fact. Yet, we often teach color theory as if it were irrefutable: Red, yellow, and blue are the primary colors that make up all other colors. Two primary colors make a secondary color.
The brain uses light signals detected by the retina's cone photoreceptors as the building blocks for color perception. Three types of cone photoreceptors detect light over a range of wavelengths. The brain mixes and categorizes these signals to perceive color in a process that is not well understood.
Eigengrau (German for "intrinsic gray"; pronounced [ˈʔaɪ̯gŋ̍ˌgʁaʊ̯]), also called Eigenlicht (Dutch and German for "intrinsic light"), dark light, or brain gray, is the uniform dark gray background color that many people report seeing in the absence of light.
Imagine a colour other than red, orange, yellow, green, blue, indigo, or violet. You can't, right? That's because it's impossible for the human brain to comprehend a colour not already present in our visible spectrum.
Red-green and yellow-blue are the so-called "forbidden colors." Composed of pairs of hues whose light frequencies automatically cancel each other out in the human eye, they're supposed to be impossible to see simultaneously. The limitation results from the way we perceive color in the first place.