2004.08.09 17:37 "RE: [Tiff] Technotes", by Ed Grissom

Here is a copy of TTN1 that I have. I think that this was the only existing TTN at the time that Tom Lane wrote the Draft TTN2. Note that the date on it is 1993, which is a year or so before Tom published his note. There was at least a couple of months discussion on the JPEG list and may have been on the LibTIFF list as well before Tom authored his note.

I think that Adobe may have been unaware of Tom's Draft TTN2 when they published their TTN1,2,3, and 4 in the TIFFPM6.pdf file a year or so after Tom sent his out to the mailing lists.

Then when they went to include Deflate and the new defacto standard JPEG, they drew a lot from Tom's draft document. They seem to have lost the numbering as well, but I'm not certain that that means a whole lot -- the title is more important anyway.

As far as I know, there are no significant differences between Tom's draft and the Photoshop "enhancement" doc. At least Photoshop can read my files and I can read theirs.

In the "Draft TTN2" if you go down to the "Replacement TIFF/JPEG Specification", it is nearly word for word from there to the end of the document in the Photoshop document. The only changes I could see dealt with detailing Photoshop's support for certain features. The initial part of the "Draft TTN2" document is rationalization for why we needed a new spec, and Adobe was right not to include it in the new spec.

ed grissom
ed.grissom@intergraph.com