Xref: utzoo sci.electronics:4065 comp.graphics:3345
Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!ames!eos!jbm
From: jbm@eos.UUCP (Jeffrey Mulligan)
Newsgroups: sci.electronics,comp.graphics
Subject: Re: Perceptual Color (was: Re: Looking for Blue LEDs)
Message-ID: <1692@eos.UUCP>
Date: 12 Oct 88 00:13:11 GMT
References: <987@hydra.riacs.edu>
Organization: NASA Ames Research Center, California
Lines: 20

From article <987@hydra.riacs.edu>, by julian@riacs.edu (Julian E Gomez):
> In article <175@leibniz.UUCP>, hwt@leibniz.UUCP (Henry Troup) writes:
>> I remember, long years ago (over 20, awright), seeing 'colour' on a B&W
>> TV.  One of the standard optical illusions is a black and white rotating
>> disk that shows visual brown and green.  Fascinatingly enough, this came
>> over very well on a British (25-frame? 400 line (the old British system)) TV.
 
> What you saw is known as a Fechner wheel.
 
 Is this another name for "Benham's top?"  This one is a disk
 half white and half black, with some black tangential arcs on the
 white half.  One point that is illustrated by this particular
 demonstration is that the (weak) hues evoked depend on the spatial
 context, not just to temporal pattern at the "colored" area.

-- 

	Jeff Mulligan (jbm@aurora.arc.nasa.gov)
	NASA/Ames Research Ctr., Mail Stop 239-3, Moffet Field CA, 94035
	(415) 694-6290