2003.02.14 01:24 "Obsolete JPEG encoding in TIFF files", by Chris Cox
Today I discovered one of the leading producers of OldStyle JPEG (COMPRESSION=6) - Pixel Translations (www.pixtran.com). When I contacted them to ask why they continue to produce this stype of JPEG compressed TIFF when Adobe had documented COMPRESSION=7 method almost a year ago,
We just cleaned up the notes and updated it with suppliment 2 in 2002. The type 7 JPEG update came out a long time before that. (and appears to have been deleted since we posted the cleaned up version)
"Compression type 7 does not adhere to the latest TIFF specification (version 6.0) for JPEG data. We support the JPEG compression format type 6 from that specification."
Adobe has not supported compression type 6 for many years, and the documentation for compression type 7 is on Adobe's web site (as well as in several of the Adobe product SDKs).
Even LIBTIFF has documented compression type 6 as being obsolete.....