Final answer:
Each type of cone cell in the human eye contains a different kind of photopsin, which is most sensitive to a certain range of light wavelengths, giving specificity to colour perception. The combination of signals from these cones allows us to perceive a wide spectrum of colors.
Step-by-step explanation:
The specificity of each cone to a particular colour is determined by the type of photopsin it contains, which makes it sensitive to certain wavelengths of light. The human retina contains three different types of cones, each calibrated to a specific range: S cones that are most responsive to short wavelengths (approximately 420 nm), M cones to medium wavelengths (about 530 nm), and L cones to long wavelengths (around 560 nm).
When light enters the eye, these cones are activated in varying degrees based on the wavelengths present in the light. For example, light with a wavelength of 450 nm—a bright blue light—would activate the L (red) cones minimally, M (green) cones marginally, and the S (blue) cones predominantly. The brain processes the relative activation levels of these cones to reconstruct the perceived colour.
this theory of trichromatic coding helps humans perceive a wide spectrum of colours through combinations of red, green, and blue light. This concept is mirrored in technologies like color television, where colours are represented through the combination of red, green, and blue phosphor dots.