Color is that characteristic of a visible object or light source by which an observer may distinguish differences between two structure-free fields of the same size and shape, such as may be caused by differences in the spectral composition of the light concerned in the observation. In other words, color is that perception by which we can tell two objects apart, when they have otherwise similar attributes of shape, size, texture, etc. OK, that's the textbook answer. This is admittedly unsatisfying, because color is an inherently subjective experience.
Color only exists in our minds, and putting a scientific definition together of no easy task.
The usual definition, given above, is really a circular argument. So, if an two objects look different, but have the same size, shape, texture, etc., then the way you are telling them apart is their color. Here's another answer for you. No Back to top 2. In the retina of our eye are photoreceptors that are sensitive to light.