twain is platform agnostic. Its an open standard. If you read thru the spec there are several references to Mac. That said, I have zero experience with twain outside of windows using the twain_32.dll that provides for twain support there. For macs & linux mostly I hear about people using sane, hit google for TWAIN-SANE. As to how well sane follows the protocol… yeah I dunno, but on the plus side twain isn’t by Microsoft for Microsoft.