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Re: [css3-colors] Comments on Last Call

From: David Woolley <david@djwhome.demon.co.uk>
Date: Sun, 16 Feb 2003 20:40:04 +0000 (GMT)
Message-Id: <200302162040.h1GKe4305118@djwhome.demon.co.uk>
To: www-style@w3.org

> 3.1.1. Gamma correction
> 
> I really don't see, why details for browser implementation across OSs have
> to be in the spec.

Whilst strictly speaking they shouldn't be there, except as a non-normative
appendix, this is an area that implementors are very likely to get wrong,
even with it explicitly in the standard.

There is widespread ignorance about gamma, certainly amongst amateurs,
marketing people, and programmers writing web pages (and browsers).  It
is possible that some professional designers are aware, but I suspect 
knowledge is rare there.  Only really people who specialise in 
colourimetry really know about it; browser programmers are likely to
have little technical knowledge in this area.

It is very common to find gamma 1.0 or gamma 1.45 images on commercial
web sites, and most amateurs distribute images out of their camera, which
often have gamma 1.0, and loss of significance on some channels (typically
blue and green).  On the other hand very few people seem to realise that
there is anything wrong with their over-dark and poorly colour balanced
images!

(One of the things that irritates me about image manipulation programs is
their poor support of gamma; I'd like to be able to convert to gamma 1.0,
adjust black and white levels, and then  return to gamma 2.2, without 
unecessary loss of significance, but find I'm forced to to the steps 
individually - they really need to either accumulate a transform, or
work with more colour depth than the images.)

I think every opportunity needs to be taken to stress gamma, if one is
to hope for good quality images.

Incidentally, what is describe is the effect of both hardware and OS;
Macs have gamma 1.45 because of their hardware, not their software.
Received on Sunday, 16 February 2003 15:40:09 GMT

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