AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

1998.03.24 14:29 "RE: 3-bit color RGB", by Martí Maria

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.