Sunlight includes all the colors that the human eye detects. Light containing all visible colors is called white light, therefore, sunlight is white light. When sun light illuminates an object, the object appears white if all visible colors are reflected equally. If all colors are not reflected equally, then the object appears colored. In general, light appears colored when one or more constituents of the visible spectrum are missing.
Color perception depends on the physiology of our eye and brain.
Because of these three different receptors, we are able to discriminate among a wide range of colors. Our discussion of color is based on normal color vision. Color can be obtained by either an additive or a subtractive process, however, in either case light is required to see color. Additive color mixing occurs by mixing colored beams of light. For example, when we shine both red and green beams on a white screen, we see yellow, which is the sum of red and green light, where the two colors overlap.