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Re: Linking to style sheets

From: lilley <lilley@afs.mcc.ac.uk>
Date: Fri, 7 Jul 1995 13:18:08 +0100 (BST)
Message-Id: <10587.9507071218@afs.mcc.ac.uk>
To: mikebat@clark.net (Mike Batchelor)
Cc: www-style@www10.w3.org
Mike Batchelor said:

> I've noticed another quirk, which is not really a big deal, but quirky
> nonetheless.  For red, any value less than 9 is rendered black, for blue
> also, anything less than 9 is rendered black, and for green, anything less
> than 7 is rendered black.  So you can get a darker green than you can red
> or blue. :)   Maybe its just my display...

This is a consequence of the way Arena allocates colours on displays 
with inadequate colours (ie 8bit or less). It would appear (from using 
xcmap) that Arena allocates a 128 element colour rectangle: 4 red x 5 
green x 4 blue, plus a 14 element grey ramp (16 elements including black 
and white)

This is a good way to do it, because green contributes most to the 
luminance information and we are less tolerant of big steps in luminance 
than of big steps in chrominance.

I hope to analyse the perceptual spacing of different browsers colour 
allocation strategies, but this will take a bit of time.

I hope I need not add that pages should not assign colours based on this 
observed behaviour, but should specify the desired colours and let the 
browser worry about how to represent them.

-- 
Chris Lilley, Technical Author
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Received on Friday, 7 July 1995 08:18:40 GMT

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