FW: [tig] White balancing, DVDs

John Quartel john
Wed Apr 7 11:01:33 BST 2004


 > Talking of using your eyes to (heavan forbid!) grade with,
 > does anybody else wake up in the morning with a slightly
 > blue bias in one eye and a slightly red bias in the other-
 > and it swaps over!

Here's an interesting experiment which might be related. Next time 
you're lying in the sun, close your eyes and cover one of them with 
something opaque - book, towel, shirt, whatever. After several minutes 
open your eyes again and you will have a strong blue bias in the eye 
that wasn't covered. Eyelids (and flesh in general) are translucent to 
red light - shine a torch (or "flashlight") through your hand and see 
the red light get through - so closing your eyes doesn't actually black 
everything out. It's not so easy to notice this because, to save 
ourselves from being bothered by blinking, the vision part of our brains 
switches off when we close our eyes. So your uncovered eye, although 
closed, was actually staring into a bright red void and your cones were 
adapting accordingly, hence the blue bias when you opened it again. So 
perhaps if you wake up in a bright room with one eye buried in a pillow, 
you could experience the the kind of effect described.

John Quartel
Scientist
FilmLight





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