An IFD with that tag - see https://archive.color.org/files/technotes/ICC-Technote-ProfileEmbedding.pdf
Leonard From: Kemp Watson <[email protected]> Date: Wednesday, March 4, 2026 at 5:00 PM To: Leonard Rosenthol <[email protected]> Cc: Even Rouault <[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. Isn't an ICC profile supposed to go in a TIFF tag, not an IFD? Tag 34675. W. Kemp Watson, Managing Director Objective Pathology Services Limited Toronto, Canada On Wed, 4 Mar 2026 at 15:51, Leonard Rosenthol via Tiff <[email protected]<mailto:[email protected]>> wrote: Looping back on this. Is there consensus that libTIFF’s implementation - assuming that all IFD’s point to images - is incorrect as per the TIFF specification and well known existing usage (e.g., ICC profiles, C2PA Manifests etc.)? If so, can we get a fix out ASAP? If not, what is the argument for why the current implementation is correct? Thanks, Leonard From: Even Rouault <[email protected]<mailto:[email protected]>> Date: Monday, March 2, 2026 at 1:43 PM To: Leonard Rosenthol <[email protected]<mailto:[email protected]>>, [email protected]<mailto:[email protected]> <[email protected]<mailto:[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 list [email protected]<mailto:[email protected]> https://lists.osgeo.org/mailman/listinfo/tiff -- http://www.spatialys.com<http://www.spatialys.com/> My software is free, but my time generally not. _______________________________________________ Tiff mailing list [email protected]<mailto:[email protected]> https://lists.osgeo.org/mailman/listinfo/tiff
_______________________________________________ Tiff mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/tiff
