Tim Mann wrote: Actually, DjVu doesn't use JBIG2, it uses JB2, which was AT&T's proposal to the JBIG committee which was rejected. (That doesn't mean that there's anything wrong with it.) Note that JB2 as normally used is NOT lossless even for bilevel images. It *can* be used for lossless encoding, but then it doesn't do much better than G4. So all the available DjVu tools use lossy encoding. The "better legibility" is debatable. Note that it is fundamentally impossible for a lossy compression algorithm to give a more accurate reproduction than a lossless one, however more accurate reproduction does not necesarily imply better legibility. In general I prefer to use lossless compression in the hope that OCR technology will eventually be good enough to be useful. It's always possible to run the file through a legibility filter later, but once you've used lossy compression you can't later decide you prefer accuracy. I've compared scanned docs encoded in G4 and JB2/DjVu, and when printed out the G4 looked slightly better to me. On-screen there was less of a noticable difference. It may be that the commercial DjVu viewer does a better job of scaling for display than Acrobat Reader, but that's entirely orthogonal to the compression algorithm used. My main problems with DjVu are: 1) Everyone already has Acrobat. Expecting people to install a new application to view documents I scan seems rather presumptuous. 2) The compression in DjVu is patented. There is a somewhat wishy-washy patent license for GPL'd software that may cover the AT&T patents, however the base compression technology is encumbered by other non-AT&T patents on arithmetic coding and such. All the patents on G4 compression have long since lapsed. 3) The free software to encode files into DjVu does NOT have anywhere near as good an implementation of JB2 as the commercial version, so the compression ratios are NOT the great ones claimed on the DjVu sites. 4) The company that now owns the DjVu technology has withdrawn the commercial versions from distribution. Their web site suggests that it's possible to buy them directly, but no pricing is given, nor is there on-line ordering. The old prices were quite high as compared to Acrobat. 5) PDF format is well documented, and there are MANY tools for dealing with it in various ways. For DjVu, there's not much. DjVu does have one major advantage for web access, which is that it is better for online browsing, *if* the user already has a viewer application installed. In my opinion, even if there is a slight technical advantage to JB2 and DjVu, it is outweighed by the disadvantages I've listed above. A recent version of the PDF file format added JBIG compression, but I'm not sure about JBIG2. I would avoid both and stick to G4.