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Path: utzoo!linus!philabs!seismo!harpo!eagle!mhuxl!ihnp4!inuxc!pur-ee!isrnix!akp
From: akp@isrnix.UUCP
Newsgroups: net.general
Subject: Re: Are you seeing pink walls? - (nf)
Message-ID: <1245@pur-ee.UUCP>
Date: Thu, 15-Dec-83 01:35:15 EST
Article-I.D.: pur-ee.1245
Posted: Thu Dec 15 01:35:15 1983
Date-Received: Sat, 17-Dec-83 02:39:57 EST
Sender: notes@pur-ee.UUCP
Organization: Electrical Engineering Department , Purdue University
Lines: 22

#R:cal-unix:-15300:isrnix:6500006:000:1119
isrnix!akp    Dec 14 04:45:00 1983

/./
Okay... Psych 101 was not so long ago for me, so here goes:
Your eye works by inhibiting itself. If a cone is hit by light, it "fires"
more rapidly, sending a "light" message to the Optic Nerve (indirectly).
As a side-effect, the firing is building up some waste material, which
in turn inhibits the cone which is firing AND THOSE AROUND IT. If you look
at the sun (on the right kind of day), you'll start seeing a bluish disk
blocking it; that's the result of the yellow-sensing cones being inhibited;
you sense more blue.  Same thing goes for green screens: the green receptors
are busy inhibiting each other, and when you look away it takes a bit for
them to recover. During that time, the red sensors are still as active as
normal, and the green ones are inhibited, so you see "extra" red on everything
(relatively speaking), especially light-colored (white) things.

	The above is a simplification. The "yellow" sensors are actually
a combination of the blue and the green, and all that inhibiting is more
complex than that, really.  But you get the idea.		-- Allan Pratt
					...decvax!ihnp4!iuvax!isrnix!akp