The Information Interchange Model
The IPTC and the Newspaper Association of America (NAA) had begun to work jointly in 1990 to design a globally applicable model for all kinds of data. As a result from this effort in 1991 the "Information Interchange Model - IIM" version 1 was approved and further developed since then. After the advent of new technologies for data representation - primarily XML - the development of IIM has been frozen in 1997, only a minor change has been applied in 2014. The latest version is 4.2.
Metadata elements of IIM are quite well-known as "IPTC fields" in the "IPTC header" of digital image files. Adobe Systems Inc. invented their own mechanism to insert metadata structures into Photoshop, JPEG and TIFF files but adopted the data structure of IIM and several of its metadata elements. This mechanism of inserting metadata was implemented by other software vendors as well, therefore many image library programs are able to read and write these "IPTC Headers". Find more about using IIM fields with photos in the Photo Metadata section of this website.
Besides this specific use the IIM model is designed to provide for universal communications embracing all types of data, including text, photos, graphics, etc. on a single network or a single storage medium. A mechanism is provided to use existing formats during transition.
IIM assumes that the sender wishes to transfer a data object, such as a photographic image, text or perhaps a combination of many types. An envelope is provided around the object for information as to the type of data and the file format. Additional information, such as caption, news category or dateline also is included. The object itself is transferred, together with information regarding the size of the data. Thus any form of computerised data could be transferred, together with pertinent editorial and technical information.
Older practice consisted primarily of rigidly formatted "headers" with a number of required fields denoting such things as story priority or category. The IIM has relatively few required pieces of information. Instead, the information about the object consists of "DataSets," each with its own identifier. Only those DataSets required for an application are mandatory. Other DataSets are optional and are utilised only when the provider deems it necessary to do so.