What is color?

Color is a subjective psychophysical experience caused by electromagnetic radiation in between wavelengths of 380 to 750 nanometers. 

Subjective because every one of us perceives colors differently - green is still green for all of us but we do not see the same tone of the color.

Psychophysical because both physical and psychological factors are included in the process. Physical factors are the electromagnetic radiation and the material characteristics that a colored object possesses. Our own color perception and "state of mind" are the psychological factors.

Because of this, we are able to define color in 3 different ways:

• As a material characteristic of an object
• As a physically measurable stimulus (we can measure the dominant wavelength to determine the color of an object)
• As a subjective abstract experience

How do we perceive an object to have a specific color?

The most simple explanation I can think of is: If an object is in complete darkness, there is no color. When we emit light onto an objects surface, it absorbs and reflects certain parts (wavelengths) of the visible specter (between 380 and 750 nanometers). The wavelengths that an object reflects or absorbs are determined by the chemical characteristics of the material the object is made of or of the substance it is "painted" in. Wavelengths which are absorbed are turned into heat energy and the wavelengths that are reflected from the object into the space around it define the colors that we see when we look at it.

Interesting fact: You may have noticed that if you wear a black T-shirt during a sunny day you will pick up much more heat than you would if you wear any other color - white will pick up the least. This is because the color black absorbs almost all of the wavelengths while the color white reflects almost all of them.