The short answer
EXIF is what the camera recorded. IPTC is the news and photo industry's standard for describing an image: caption, keywords, creator, rights and location. XMP is the container current software uses to store IPTC fields and much more. A typical photo carries all three, and some values, such as the caption, the creator and the date, exist in more than one of them.
| What it is | Who writes it | Typical fields | Where it lives | |
|---|---|---|---|---|
| EXIF | Technical data recorded by the camera or phone | Cameras and phones, when the photo is taken | Date taken, camera and lens, exposure, GPS location | A binary block inside JPEG, HEIC, TIFF and most RAW files |
| IPTC IIM | The original news-photo record for captions, credits and rights | Older software and many newsroom systems | Caption, keywords, byline, copyright, city | A binary block in JPEG and TIFF, with byte limits per field |
| XMP | An extensible XML container for any kind of metadata | Current photo software: Lightroom, Bridge, Photo Mechanic, Parergon | The IPTC Core and Extension fields, ratings, edit history, AI disclosure | Embedded in most formats, or in a separate .xmp sidecar file |
Scroll the table sideways for the remaining columns
EXIF: what the camera recorded
EXIF is published by the Japanese camera and electronics industry associations CIPA and JEITA. Cameras and phones fill it in at the moment of capture: date and time, camera and lens, exposure settings, and GPS when location is on. Its dates have no time zone unless the offset fields are written too, which is why travel photos so often end up hours off. Exif 3.0, published in 2023, added UTF-8 text, so names with accents no longer have to be squeezed into plain ASCII.
IPTC: the words that describe the picture
IPTC, the International Press Telecommunications Council, defined its Information Interchange Model (IIM) in the early 1990s so news photos could carry captions and credits between agencies. IIM is compact and binary, and it limits many fields to a few dozen bytes. Today's IPTC Photo Metadata Standard keeps the same ideas in two schemas, IPTC Core and IPTC Extension, stored in XMP. The IPTC standard explained covers what is in them and what each version added.
XMP: the container
XMP was developed by Adobe and is now the international standard ISO 16684. It stores metadata as XML, holds far longer text than IIM (very large packets in JPEG need an extension some apps ignore), supports several languages per field and can hold any schema: IPTC Core and Extension, Dublin Core, ratings, edit history and the new AI-disclosure fields. It is embedded in most formats; for camera RAW files some apps keep it in a separate .xmp sidecar instead.
Why the copies disagree
- One value, several homes. A caption can sit in XMP
dc:description, IIM caption 2:120 and EXIF ImageDescription. An app that updates one and not the others leaves them out of step. - IIM is short. A long caption or keyword is cut off in IIM while XMP keeps it whole, so apps that read IIM show a truncated text.
- Character sets. Older IIM text is not always UTF-8, so accents can turn into strange characters in one copy and look fine in another.
- Sidecars. When one app writes a sidecar and another reads the embedded copy, each sees a different version of the truth.
The Metadata Working Group, an industry group including Adobe, Apple, Canon, Microsoft and Sony, published guidelines on which copy should win and how software should keep them in step. In short: write all copies together, and when they differ, trust XMP unless the IIM copy was clearly changed later.
How to see what a photo really carries
- Parergon shows every copy of a field side by side, warns when copies disagree, and writes them together when you edit. Viewing is free.
- The free online metadata viewer shows EXIF, IPTC and XMP for a JPEG or PNG in your browser, without uploading it.
- ExifTool lists every tag with the block it came from:
exiftool -a -G1 photo.jpg.
For the exact name of each field in every standard, from the ExifTool tag to the IIM dataset, see the field reference.
