5 ms·
Let's assume you're correct, and that the more-or-less logarithmic aspect to human vision is inconsequential here, and also that the hump in absorption around 4
by blincoln 8y ago
Let's assume you're correct, and that the more-or-less logarithmic aspect to human vision is inconsequential here, and also that the hump in absorption around 410nm by the red cones is also irrelevant. How would you explain the human perception of violet light as a purple colour, then?
- jacobolus 8y agoBy “violet light” you mean a 400 nm laser or something? Or a blacklight? https://en.wikipedia.org/wiki/Blacklight https://en.wikipedia.org/wiki/Blacklight In normal circumstances (say, daylight surroundings), a moderate amount of light at very short wavelengths won’t look like much of anything at all, bluish–black, because the cone cells (especially L and M cones which determine red–green response) will be getting much more stimulus from other wavelengths. If you go to a completely dark room, let your eyes adapt, and look at a blacklight, then you are right that you are at that point going to see it looking purplish because the L cones are stimulated a bit more than the M cones for those wavelengths, and other wavelengths are entirely absent. But this is a really weird edge case for vision.
- Bendingo 8y agoThe first sentence in the wikipedia article says: "A blacklight [...] emits long-wave (UV-A) ultraviolet light [...]." Why does it say "long-wave" when UV is short-wavelength ?
- OscarCunningham 8y agoBecause the light that blacklights emit is on the longer end of the possible UV wavelengths. This is what the UV-A means. There are also UV-B and UV-C with shorter wavelengths.