Why do i see green ?

Got a free pair of sunglasses that have lenses with a purple tint. When I take them off, everything turns green. Why?

http://www.michaelbach.de/ot/col-lilacChaser/index.html

Hi david, attached self-demo that helps. Open that image and crank your screen brightness all the way up. Stare at the magenta circle for a minute and then look at the white circle down below. It looks green. This is closely related to (the inverse of) "Dark Adaptation" familiar to us Deep Sky observers. It is caused by BOTH differential chemical depletion of the red (X) and blue (Z) receptors in the cones AND depletion of the associated neurotransmitters (awaiting "reuptake"). You can do that with any of the other primary colors and their compliments. This also relates to going into a DARK movie theater from sunlight and being temporarily blind and the inverse affect of being dazzled upon emerging a couple hours later. We astronomers typically associate Dark Adaptation only with the rods --- but it substantially affects the cones too! Ummmmmm... when I was 17, I worked at the Boynton Center for Visual Science at the University of Rochester. Ran experiments there and constantly talked physiological optics with the teachers and grad students. The Eye is an extraordinary instrument! Tom Dey

Attached Image:

Good! I just looked at dan's link there and it is dramatic. By extension, the same sort of thing can be done with any color leading its compliment. And that's also why artists like to work in compliments --- because they mutually enhance colors, making them feel "electric." Come to think of it --- why complimentary-colored double stars look SO colorful! What we call "color contrast." On top of all that ... color perception and discrimination vary wildly among people, just as do their senses of taste. Tom