1999.12.01 14:42 "ZIP compression [was: libtiff 3.5.3 release.]", by Tom Kacvinsky
As you may or may not know, Adobe's Image Ready support ZIP compressed TIFFs (reading and writing), but they use a different tag for the compression scheme. ZIP compressed TIFFs as built by tiffcp cannot be opened in Image Ready, and vice versa. So it lloks like Adobe is already heading torwards adding ZIP compression to the TIFF specification, but is using a different tag scheme. I belive that Leonard Rosenthal (of Adobe) is on this list and could answer this question.