Standards: IPTC-IIM

The IPTC-IIM schema got it all started and remains a widely used and recognized format.

 

 

While now considered a legacy format, the International Press and Telecommunications Council’s original schema is widely recognized by software products that access metadata, many of which cannot read or write the more recently defined IPTC Core/XMP schema.

 

Based on a format for text files that described accompanying media, the IPTC’s Information Interchange Model (or IIM for short) launched in 1991, providing a new way to handle “digital resources” with metadata and content held in a binary-structured framework. In the mid-1990s, Adobe added the ability to insert descriptive metadata in TIFF and JPEG digital image files, giving birth to IPTC headers. An Adobe-specific container or “wrapper,” dubbed the Image Resource Block (IRB), encapsulated a subset of the IPTC’s IIM metadata structure, allowing editing through the Photoshop "File Info" dialog.

The IIM as introduced was designed for describing all types of media (articles, images, etc). Some of the early digital imaging programs (like Photoshop) found it to be particularly useful set of values, and a subset of them were adopted by the photographer community. After the release of the IPTC Core in 2005, it was no longer the only method of embedding photo metadata, and the tide has been slowly turning. Many of the better applications embraced the XMP method of storing metadata, but maintain backwards compatibility with the IIM standard by synchronizing the data and writing the saved values (for any shared fields) into both the IIM and XMP containers.

Many third-party developers have created software applications that read and write to IPTC headers. But some consider it metadata “black art,” since the storage location and structure vary with image file formats. Occasional glitches appear in how certain diacritical characters - such as accents, tildes, umlauts, etc. (áçèîñõü) - translate when exchanging files between operating systems. This schema also has specific limits on the number of characters each field can hold.

For specifics on the various field names used in different imaging applications, you might want to download the IPTC Core mapping chart on the Controlled Vocabulary website
 

IPTC Official Website: http://www.iptc.org/