I was thinking about using JPEG2000 to archive scan masters, because I hate the look of original JPEG artifacts. In the end I decided to go with FLIF to eliminate the "preservation risk" - by being lossless, I can run the output through sha256 to make sure I've gotten all the original bits back. In the event that I regret this decision, I can simply transcode and not feel too bad (as opposed to transcoding from lossless and losing even more quality).