photo-metadata

# Photo metadata ## Overview Metadata embedded in an image file travels with the file. Photo CMSs (Photo Mechanic, Lightroom, Capture One) and wire intake systems read a photo's caption, credit, and rights from its IPTC and XMP blocks, not from a separate document or the email it arrived in. If the caption, credit, alt text, and license are not *inside* the file, they are gone the moment the photo is downloaded, forwarded, or re-uploaded. One `exiftool` pass writes the EXIF, IPTC, and XMP layers together and leaves every other tag (camera settings, shot time) untouched. Modern software reads **XMP first**, legacy IPTC-IIM second, EXIF only for date and GPS, so write XMP everywhere and add IIM as a compatibility copy on JPEG/TIFF (HEIC, AVIF, and WebP have no IIM slot at all; see `reference.md`). Two things changed since this workflow was "caption, credit, copyright." First, **how an image was made now belongs in the metadata**: the IPTC *Digital Source Type* field labels a camera photo versus an AI-generated one, and platforms (Meta, Google) and the EU AI Act increasingly read it. Second, **cryptographic provenance (C2PA / "Content Credentials")** is arriving on wire images and cameras, a signed layer `exiftool` can *read* but not write. Both are covered below. **A capable model already knows the field names.** The hard part is not the mechanics, it is the judgment below. Lead with that. ## When to use - Prepping press photos for a wire so partner newsrooms can search,...