What is color?

 

Color is quite complex. There is not one source but rather three different sources of color. Color always includes three things - light, our eyes (which is how we detect the light) and the object (which we will identify as colored). The color of our object can have three different origins which can be labeled as absorption, emission and scattering. The lightning is a result of emission. And the blue of the sky and the colors of the rainbow are caused by scattering. Each different form of color - absorption, emission and scattering - occurs naturally - grass, lightning and rainbows without the participation of man. Humans, in making their life so much more colorful, have simply exploited these natural effects.
In absorption, light (sunlight which is white light) strikes an object and part of the light may be absorbed by the object. The light we see coming from that object is the light which was not absorbed by the object. Humans see the "not-absorbed" light as the color of the object. If there is no light absorbed, the object appears to be colorless. Vegetation absorbs all the light except green light and that absorption, possibly the most important process on earth, drives photosynthesis and makes life on earth possible. The paints and dyes shaped by man as artificial colorants appear colored for the same reason that grass appears colored: they absorb some of the light that strikes them.
In emission, the object makes colored light and "throws" it at us. It in fact does no "make" light because it cannot "make" energy. Humans can only transform energy from one form into another.
Color is a micro consciousness. Like humans senses of taste and smell, color helps us to understand the world around us. It helps humans survive as a species, and appreciate works of art.
In the late 19th and early 20th centuries, many artists examined the "essence" of things, and divided the visual experience into components, such as "color" and "form," in a manner surprisingly similar to how human brain processes information. Human mind continually seizes essential information from the continually changing information we see, distilling from the successive views the essential character of objects and situations.
Color is a property of objects that our minds generate - an interpretation - and this property is unique to humans and higher primates. This interpretation helps humans acquire knowledge about the properties of surfaces. To construct colors, human's subconscious mind analyzes ratios of the signals from photoreceptors in the retina. Nowadays, researchers are studying how the nerve cells in critical areas of the brain undertake the ratio-taking operation.
Without this approximate constancy, a banana would not appear as a banana each time we see it. Similarly, a piece of chalk on a cloudy day would manifest the same color as a piece of coal does on a sunny day, and in the course of a single day, it would have to assume all possible colors that lie between black and white.