IPTC Photo Metadata Standard
The IPTC Photo Metadata Standard is the most widely used standard to describe photos, because of its universal acceptance among news agencies, photographers, photo agencies, libraries, museums, and other related industries. It structures and defines metadata properties that allow users to add precise and reliable data about images.
In the early 1990s, the original “legacy” IPTC-IIM (Information Interchange Model) schema was developed to organise, systematise and unify the way information was stored and transported with images. Prior to IPTC-IIM, every management system had its own way of handling metadata, which did not transfer data between other software and file formats.
Today, the IPTC Photo Metadata Standard consists of two schemas – IPTC Core and IPTC Extension – which were built on the legacy of the original IPTC-IIM, and developed by the IPTC for professional use with a focus on news and stock photos. IPTC worked alongside Adobe on the technical implementation of the metadata that employs Adobe’s XMP technology (now an ISO Standard) as an enriched alternative to the IIM format.
IPTC Core and IPTC Extension define metadata properties with comprehensive sets of fields that allow users to add precise and reliable data about people, locations, and products shown in an image. It also supports dates, names and identifiers regarding the creation of the photo, and a flexible way to express rights information.
Reference Images using all IPTC Photo Metadata fields
You can view and download an image file which includes all metadata fields defined by each version of the IPTC Standard:
If you check this image with some imaging software you should see a value of the field reflecting the name of the field. For example, the value of the Creator field should be “Creator (ref2019.1)”.
The IPTC Photo Metadata TechReference
IPTC provides a machine-readable version of the specification that can be consumed directly by software tools. We call it the IPTC Photo Metadata TechReference.
The TechReference is a data object containing all the details of the IPTC Photo Metadata technical specifications in the easy-to-use JSON and YAML formats.
IPTC has published rich documentation about the TechReference data object and the data objects themselves can be downloaded from the IPTC site by both IPTC members and other interested parties:
- Documentation on the TechReference data object
- The standard version 2021.1 data object in JSON format: https://iptc.org/std/photometadata/specification/iptc-pmd-techreference_2021.1.json
- The standard version 2021.1 data object in YAML format: https://iptc.org/std/photometadata/specification/iptc-pmd-techreference_2021.1.yml
What’s New in recent versions of the Standard
What’s New in the 2021.1 Standard
The 2021.1 version, published in November 2021, introduces the Alt Text (Accessibility) and the Extended Description (Accessibility) properties. These will make it easier for software companies, publishers, and website developers to make websites and electronic publications more accessible.
Further it introduces the Event Identifier property complementing the Event property holding the name of an event.
What was New in the 2019.1 Standard
The 2019.1 version, published in December 2019, introduced IPTC Image Regions. Shapes within an image can be marked up as rectangle, circle or polygon, and any existing IPTC Photo Metadata field can be added to a region. In addition, two new properties, Image Region Content Type and Image Region Role, were added to describe characteristics of a region.
What was New in the 2017.1 Standard
The 2017.1 version of the IPTC Photo Metadata Standard, published in June 2017, added these fields to the Extension schema:
- Property Image Rating. It adopts the “star rating” defined by XMP as part of the IPTC Standard.
- Property Web Statement of Rights. It adopts the property defined by XMP and labeled “Copyright Info URL” by many software tools as part of the IPTC Standard.
Note: The standard document is now published as a web page, it was a PDF in the past. The web page has a print-friendly stylesheet so it can be printed directly from the web version.
What was New in the 2016 Standard
The October 2016 version of the IPTC Photo Metadata Standard includes the addition of these fields to the Extension schema:
- Structured property Genre. Extends the semantics of Intellectual Genre of the IPTC Core and allows the use of terms from Controlled Vocabularies.
- The Registry Entry structure was extended by a Role element to indicate the role of this entry among other Registry Entries.
What was New in the 2014 Standard
The October 2014 version of the IPTC Photo Metadata Standard includes the addition of these fields to the Extension schema:
- Structured property Person Shown in the Image with Details. Includes fields for the name, identifiers, characteristics and a description of a person.
- Structured property Product Shown in the Image. Includes fields for the name, a GTIN identifier and a description of a product.
- Structured property CV-Term About Image. Includes fields to precisely express a term from a controlled vocabulary, including names in different languages, its identifier and more.
- Additional properties for the Artwork or Object in the Image structure. More detailed descriptions of the work, contributions to the work, circa dates of creation and style period, as well as rights data.
- Containers for machine processable Rights Expressions in different languages. One embeds the expression, another one links to an expression as a web resource.
What’s Defined by This Standard
The IPTC Photo Metadata Standard provides a structure for fields as well as descriptions for how fields should be used, and what information should be included.
The IPTC Photo Metadata Standard also specifies two technical formats for storing the information externally of image files:
- XMP: Developed by Adobe in 2002, and now maintained by ISO. It uses the Resource Description Framework (RDF) data model and XML as serialization syntax.
- IIM: It uses a genuine data model and binary structures to save the data.
How Photo Metadata formats are stored internally of image files are defined by non-IPTC file format standards, such as JPEG/JFIF, TIFF, PNG and more.