“Humans can only perceive colors that are in the rainbow.”

It's a common misconception that human vision is confined exclusively to the vibrant array of colors displayed in a rainbow. This belief is understandable, as the rainbow serves as a universally recognized and simplified model of the visible light spectrum. From childhood, we learn about red, orange, yellow, green, blue, indigo, and violet as the fundamental components of light, leading to the natural assumption that anything outside this familiar band is simply beyond our visual grasp. We don't consciously experience colors like "infrared" or "ultraviolet" in the same way we see blue or green, which reinforces the idea that our perception is strictly limited to the visible spectrum.

However, the reality of human light perception is more expansive than this simple model suggests. While the visible spectrum does represent the core range of light frequencies we perceive as distinct colors, our eyes can actually detect light just beyond red, in the near-infrared range, and slightly past violet, into the near-ultraviolet. We don't interpret these as new, distinct hues, but our photoreceptors can register their presence under certain conditions. Moreover, a fascinating biological variation exists: some individuals, primarily women, are tetrachromats. They possess a fourth type of cone cell in their retina, potentially allowing them to perceive millions more colors than the average person, vastly expanding their chromatic world beyond the rainbow's limits.