Re: Color Palette Incompatibilitiesq

Lee Daniel Crocker (lcrocker@calweb.com)
Fri, 6 Sep 1996 10:52:41 -0700 (PDT)


Message-Id: <199609061752.KAA17455@web1.calweb.com>
Subject: Re: Color Palette Incompatibilitiesq
To: boo@best.com (Walter Ian Kaye)
Date: Fri, 6 Sep 1996 10:52:41 -0700 (PDT)
From: "Lee Daniel Crocker" <lcrocker@calweb.com>
Cc: www-html@w3.org
In-Reply-To: <v0300780488b67cb29dd6@[205.149.180.135]> from "Walter Ian Kaye" at Sep 5, 76 05:02:37 pm

> > These colors were originally picked as being the standard
> > 16 colors supported with the Windows VGA palette. The above
> > gives the sRGB values in hex (#RRGGBB).
> 
> There is a problem with half of these colors -- "80" and "C0" are not in
> the 216-color dither-free cross-platform palette used by Netscape, Mosaic,
> and Internet Explorer. The included codes are 00, 33, 66, 99, CC, and FF.
> 
> I'm not crazy about the palette (only 4 shades of grey?!), but it *is* the
> standard cross-platform palette.

There is nothing either "standard" or "cross-platform" about the 216-
color hack.  The existence of limited palettes at all, and the the
specific sizes of them, are platform dependencies.  And those "standard"
values of 33, 66--what gamma are they at?  Your 66 might be my 80.
There is no usefulness to it anyway--even if one is meticulous to
dither every picture you have to that palette so the NSN and MSIE will
show it pixel-for-pixel, you are still not guaranteed that your image
will even vaguely resemble your original on any machine, even with
that software, because of different monitors, DACs, and other problems.
The best you can do is use an image format capable of specifying colors
precisely in physical terms (like PNG), and hope someday browsers will
pay attention to it.

If HTML wants to handle precise color (it might at some point), then it
needs to treat colors as the physical properties they are, not the way
some piece of computer hardware built to save RAM does.  I'd even like
to see those standard colors expressed portably (say, CIELab) instead of
in meaningless RGB.

--
Lee Daniel Crocker <lee@piclab.com>