Just sitting here pondering if color blind people can see colors they cant see normally when under the influence of a psychedelic? Any first hand exp. from someone here that could answer?

My friend has a green red deficency and he says its pretty much the same like usual. So he doesnt see any new colors but then again he does see colors still. Just different from what non impaired people see.
Also the visual effects like color shifting and brightness changes still apply to him like to others.
Dont forget that like 9% of european males have that deficency to some extent. His is just so strong that he cant tell apart any shade of red from any shade of green.

A friend of mine has less severe green colour blindness and says that psychedelics lessen the impairment and the effect can persist for weeks or months even afterwards before fading.
I discussed with him whether he is really seeing green though or just some enhanced shade, we were unable to figure the merit of that out.

This can presumably be tested using the usual colourblindness test figures.

It would be even more interesting to see if/what a person will experience if he was blind since birth on DMT.

Highly interested in this topic! As an medical practicioner I would say that Im hard-pressed to believe the issue with a particular photoreceptor can be altered once a psychedelic trip is over. It's a anatomical change and a mutation at the level of the chromossome, ultimately affecting a photoreceptor in the eye. Having said that, the brain is still the structure that interprets vision. If you imagine a psychedelic trip in comparison to an out of body experience, you may be seeing colors you normally don't (depending on what you are getting there/time/intensity/stage of the experience) and carry it over a little to the physical realm immediately after. But I doubt it's a lasting effect.

Im curious to hear what a blind person would experience. It's probably not too different than what we experience, as the notion of vision is not foreign to your higher self, but likely with a shit load joy and happiness that in the beginning exponentially surpasses ours (visual beings).

I've always had a hard time making the distinction between blues and purples, as well as browns and reds. Since utilizing entheogens as tools for healing, i can honestly say that my vision has changed and i have become less color blind, able to make these distinctions more clearly and with more surety.