IPTC Information Interchange Model

The Information Interchange Model (IIM) is a file structure and set of metadata attributes that can be applied to text, images and other media types. It was developed in the early 1990s by the International Press Telecommunications Council (IPTC) to expedite the international exchange of news among newspapers and news agencies.

The full IIM specification includes a complex data structure and a set of metadata definitions.

Although IIM was intended for use with all types of news items — including simple text articles — a subset found broad worldwide acceptance as the standard embedded metadata used by news and commercial photographers. Information such as the name of the photographer, copyright information and the caption or other description can be embedded either manually or automatically.

IIM metadata embedded in images are often referred to as "IPTC headers", and can be easily encoded and decoded by most popular photo editing software.

The Extensible Metadata Platform (XMP) has largely superseded IIM's file structure, but the IIM image attributes are defined in the IPTC Core schema for XMP and most image manipulation programs keep the XMP and non-XMP IPTC attributes synchronized.

Because of its nearly universal acceptance among photographers — even amateurs — this is by far IPTC's most widely used standard. On the other hand, the use of IIM structure and metadata for text and graphics is mainly limited to European news agencies.

IIM attributes are widely used and supported by many image creation and manipulation programs. Almost all the IIM attributes are supported by the Exchangeable image file format (Exif), a specification for the image file format used by digital cameras.

IIM metadata can be embedded into JPEG/Exif, TIFF, JPEG2000 or Portable Network Graphics formatted image files. Other file formats such as GIF or PCX do not support IIM.

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