2007.05.13 17:47 "[Tiff] JBIG2 compressed TIF question about bpp", by t t

Hi everybody,

I've used this site many times before to look up TIFF tags and look at the TIFF specification. My question is about a JBIG2-compressed TIF. Now I know JBIG2 is a bitonal compression standard, but if you save let's say a 24-bit TIF with JBIG2 compression should it work according to the specification or do you have to start with a 1-bit TIF first?

I'm using some imaging software and I can successfully start with a 24-bit TIF and save it as a PDF with JBIG2 compression so it's 1 bit. But if I start with a 24-bit TIF and save it as a TIF with JBIG2 compression an exception is thrown, but if start with a 1-bit TIF and save it as a TIF with JBIG2 compression it works fine as it should. I know if you start with a non 1-bit TIF and save it with G4 compression it will take it to 1-bit without a problem.

I found a very similar question in the archives here where somebody wanted to save a non 1-bit TIF with RLE encoding but the TIF specification doesn't support that and he would have to take it down to 1-bit first to do it.

So is this a problem with the software I'm using or does the TIF specification not support it?

Thanks,

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