Color is more than just a property of an object. It is the result of
a complex perception mechanism that takes place in the eye and brain of
an observer automatically, whenever he is looking at an object. The color
is a result of an evaluation process of incoming light into the retina
in the eye, and the neural processing of the retinal response by the brain.
Color perception of individual human beings strongly depends on their
color perception capabilities. So it would be better to talk about color
impression than color.
The eye is sensitive to a broad band of wavelengths with the approximate
range 350-750 nm. The visible spectrum represents only a small fraction
of the full electromagnetic spectrum. However, within the visible spectrum
certain wavelengths give rise to certain visual sensations. For example,
the shorter wavelengths are perceived to be violet and blue whereas the
longer ones are perceived to be red.