Leonard, where is the Adobe TIFFtag registry? It's been AWOL for years, good to hear it still exists...
W. Kemp Watson, Managing Director Objective Pathology Services Limited Toronto, Canada On Mon, 2 Mar 2026 at 13:51, Leonard Rosenthol via Tiff < [email protected]> wrote: > Yes, the C2PA TIFF tag is registered with Adobe and specific details on > TIFF embedding at > https://spec.c2pa.org/specifications/specifications/2.3/specs/C2PA_Specification.html#_embedding_manifests_into_tiff_based_assets > > TIFF already supports using IFDs for things other than images - consider > ICC profiles, for example. > > Leonard > > *From: *Even Rouault <[email protected]> > *Date: *Monday, March 2, 2026 at 1:43 PM > *To: *Leonard Rosenthol <[email protected]>, [email protected] < > [email protected]> > *Subject: *Re: [Tiff] Libtiff failing on TIFFs with embedded C2PA > Manifests? > > *EXTERNAL: Use caution when clicking on links or opening attachments.* > > > Seems to me like a weird design to hijack a IFD (*Image* File Directory) > to put something different in it. Why not having used a TIFF tag in the > first IFD for example ? But I assume my question is mostly moot now if that > C2PA spec has progressed beyond being a draft? > > I guess if someone wanted those files to be read by libtiff, the best > course of action would be to silently ignore that final IFD, or just emit a > warning instead of an error ( I assume there must be a spefic TIFF tag to > recognize it?) > > Even > Le 02/03/2026 à 19:30, Leonard Rosenthol via Tiff a écrit : > > A person reported (https://github.com/contentauth/c2pa-rs/issues/1894) > that libtiff-based apps are failing to process TIFF files with embedded > C2PA Manifests ( > https://c2pa.org/specifications/specifications/2.3/specs/C2PA_Specification.html). > I’ve commented there that I don’t agree with their position on the > topic, nor can I verify their results. > > Would love for any/all of you to comment on the situation - either here or > there. > > Thanks, > Leonard > > > _______________________________________________ > Tiff mailing > [email protected]https://lists.osgeo.org/mailman/listinfo/tiff > > -- http://www.spatialys.com > My software is free, but my time generally not. > > _______________________________________________ > Tiff mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/tiff >
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