scope:

Purpose and Scope

The purpose of this data dictionary is to define a standard set of metadata elements for raster images. This standard only applies to still raster (bitmap) images and does not address other image formats such as animated raster, vector, or motion picture. The data documents digital images created through digital photography or scanning, as well as those that have been altered through editing or image transformation (migration).

This data dictionary presents a list of technical data elements relevant to the management of digital still images. In this context, "management" refers to the tasks and operations needed to support image quality assessment, image data processing, and long-term maintenance throughout the image life cycle. "Quality assessment" is defined broadly, as it refers both to machine operations and curatorial evaluations. Technical metadata have been identified to "anchor" meaningful attributes of image quality that can be measured objectively, such as detail, tone, color, and size.

Early versions of this standard frequently referred to images maintained in TIFF (Tagged Image File Format). This final version of the standard has been expanded to allow the documentation of other image file formats. It is important to note that the standard was designed with the bias toward the documentation of master image files. While most of the technical metadata will be available and harvestable from the image file itself, many of the data elements such as image production information are not inherent to the file and will need to be added by the creating institution. Recording these additional data elements adds time and cost and therefore it is understood that it will only be cost-effective to record and maintain the technical metadata for master images. The technical dictionary documents the information and metadata all image files may contain as well as additional information related to image production.

Metadata Out of Scope

Except for documentation of the systems that were used to create an image, metadata to document provenance, authenticity, or other aspects of image integrity are beyond the scope of this dictionary. Similarly, Intellectual Property and Rights (IPR) metadata, including ownership responsibility, is not covered. Although such metadata may be integral to digital repository development and asset management, other emerging standards such as the preservation metadata data dictionary developed by the PREMIS working group and the DOI Namespace initiative address this type of metadata. As stated above, data elements in this dictionary focus upon the object class of digital still images. Even with this fairly strict definition, there may be some crossover of basic digital object information between this data dictionary and the others such as the PREMIS data dictionary. Because of this, efforts were made early to achieve harmonization across the sets, resulting in this data element set which can stand alone or be used as a part of a broader metadata set like PREMIS