I heard that the violet in rainbow is only created because the bottom blue coincides with another inner rainbow’s top red. I forgot where I heard it but it sounds logical.
Whenever I see the EM spectrum, it always goes from red to green to blue then to VIOLET which I don’t know how it got there. What bothers me more is how there’s an infraRED and then it goes ultraVIOLET.
I remember in preschool that red + blue = violet so where did the red from the violet part of the spectrum comes from?
In: Physics
Our perception maps to how activated the cones attributed to three colors are, not directly to the wavelength of incoming light. You can see a full explanation [here](https://midimagic.sgc-hosting.com/huvision.htm). This becomes quite complex for mixes of wavelengths, but for single wavelengths you can see that it does smoothly activate the red cone, then the green cone, then the blue cone – but at the very end, the red cone is slightly more activated. This is what causes the subjective similarity between violet and a mix of pure blue and pure red.
Latest Answers