When people can see ultraviolet, what is the color they see?

Over the years they've done plenty of vision studies involving ultraviolet, both on normal people and aphakics (people missing a lens in at least one eye). The color varies depending on the intensity. At high intensity it tends to look white or grey, at low intensity like grayish violet. read more

(Normally people can't even focus that close, but at 310 nm they can.) Between 310 and 302 nm the opacity of both the lens and cornea increase by several orders of magnitude. At 302 nm people only see a gray blur, and only with 1-hour dark-adapted eyes and if the uv is intense. read more

While it's possible to see black-light lightbulbs and see the darkish cast they throw on objects that don't glow ultrawhite under them, most humans can't actually see the color of ultraviolet light. Most people are able to see wavelengths of light ranging from 380 nanometers to 750 nanometers in frequency, a range that goes from dark red on the low-energy end of the spectrum, to violet on the high end. read more

People who have aphakia, or the absence of the lens on the eye, have reported the ability to see ultraviolet wavelengths. Claude Monet was one such person. Carl Zimmer writes, Late in his life, Claude Monet developed cataracts. As his lenses degraded, they blocked parts of the visible spectrum, and the colors he perceived grew muddy. read more