Why when closing eyes after looking at sun for some minutes one sees it as violet point on orange phone?

ANd when one opens eyes the point is projected first in violet,then in dark blue and then in bright green before to disapear.

Why when closing eyes after looking at sun for some minutes one sees it as violet point on orange phone?
This is called negative after-image. If you look at a spot of any color long enough, you will see the spot and its bacground in their complimentary colors when you close your eyes. Red and green, orange and blue, yellow and violet are complementary colors.





From Wikipedia:


"Negative afterimages are caused when the eye's photoreceptors, primarily those known as cone cells, adapt from the over stimulation and lose sensitivity.[1] Normally the eye deals with this problem by rapidly moving the eye small amounts, the motion later being "filtered out" so it is not noticeable. However if the color image is large enough that the small movements are not enough to change the color under one area of the retina, those cones will eventually tire or adapt and stop responding. The rod cells can also be affected by this.





When the eyes are then diverted to a blank space, the adapted photoreceptors send out little signal and those colors remain muted. However, the surrounding cones that were not being excited by that color are still "fresh", and send out a strong signal. The signal is exactly the same as if looking at the opposite color, which is how the brain interprets it.





Ewald Hering explained how the brain sees afterimages, in terms of three pairs of primary colors. This opponent process theory states that the human visual system interprets color information by processing signals from cones and rods in an antagonistic manner. The opponent color theory suggests that there are three opponent channels: red versus green, blue versus yellow, and black versus white. Responses to one color of an opponent channel are antagonistic to those to the other color. Therefore, a green image will produce a red afterimage. The green color tires out the green photoreceptors, so they produce a weaker signal. Anything resulting in less green, is interpreted as its paired primary color, which is red."





To repeat the warning given by others, looking directly at the sun for ANY period of time WILL injure your eyes. Ignoring this warning will result in


severe pain and eventual blindness.
Reply:Galileo went blind from looking at the sun dude. even history's greatest aren't immune to the effects of reality. you can visit a solar observatory and view the sun (or go to nasa's soho website for pictures updated sometimes daily and hourly. to test the persistance of vision trick safely i suggest you route here


http://www.michaelbach.de/ot/


77 optical illusions and the explination of each. be patient the site has quite a few animated graphics and takes a bit to load.
Reply:when you look at the sun rays of high frequencies fall on the eyes


When the frequency increases wavelength decreases. So you see violet first when you close your eyes as it has the least wavelenght ( about 400 nm) [although visible has a very small range of frequency 10^14]





Then as the photochemical reactions on the lens curtail then the wavelength starts increasing to reach ultimately red.





For easier understanding think of


Violet, Indigo, Blue, Green, Yellow, Orange, Red [VIBGYOR]and then see the order which you have asked question about the colors. Then I am sure you will find out the reason behind this.





Please don't look at the sun directly like that its very harmful.





Keep smiling:)
Reply:You should never look directly at the sun. Its a surpise you didn't go blind.
Reply:persistence of vision