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From: lynnand@aardvark.austin.ibm.com (/60000;Austin)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Color dithering from 256 -> 16 colors
Keywords: color graphics dithering algorithm GIF images
Message-ID: <953@awdprime.UUCP>
Date: 22 Nov 89 01:36:45 GMT
References: <7491@sdcsvax.UCSD.Edu> <5248@sdcc6.ucsd.edu>
Sender: news@awdprime.UUCP
Reply-To: lynnand@aardvark.austin.ibm.com (/60000;Austin)
Organization: IBM Austin, TX
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Color Dithering is a complex subject with no single solution. Check
technical books
on graphics and image processing for various methods and algorithms. 
The ACM Graphics SIG publications have caried articles as well.

I will check my books at home and post some specific references next week.