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March 1998

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1998.03.24 14:29 "Re: 3-bit color RGB", by Martí María

Hello,

>According to the TIFF 6.0 spec, 3-bit RGB is not allowable. Is this
correct? I don't know if 
>there have been change docs allowing things like 1,2,or 4bit RGB. Looks
like the spec 
>says 8bit only. I'd really like to be able to do 1,2, or 4 bit, but don't
want to generate something that 
>no one will be able to read.

Last week I was wondering about 'custom' compression schemes, and I found
some interesting issues. 
The ISO JBIG  compression is supossed to work with 3 bits per pixel. 
You can find more info in http://www.jbig.org 
Since the algorithm is far too complex, and licensing is required I don't
expect see the codec here, but there is an entry in tiff.h for this type of
compression. Alas, 3 bpp must be supported if JBIG is supported
elsewhere...

Regards.
Martí Maria.