ANSI/NISO Z39.87. Data dictionary - technical metadata for digital still images.


ANSI / NISO Z39.87 is a dictionary of technical metadata that contains those elements needed for the interpretation of the image, the quality assessment and the preservation. This standard, recognized as ISO 14721 since 2003, is based on the elements that should have a master image and although it is independent of specific image formats, it is inspired on the metadata of some specific formats, mainly TIFF and JPEG2000.

The highlights:

This is a comprehensive code, very useful to define the technical metadata about digital image.
It consists of 200 elements of which 21 are considered mandatory in all cases, 44 are mandatory if they exist (i.e. those belonging to JPEG2000), 36 are recommended, and the other 99 are optional.
The dictionary gives information regarding the name, the definition, the data type, the option of being repeatable, the option of being mandatory, some examples, additional notes and about the use of each element.
To make easier the implementation and adoption of the dictionary, the Library of Congress with NISO prompted the development of an XML schema called MIX (Metadata for Images in XML schema).
The elements are displayed in different categories: digital object basic information, image basic information, features of special formats (JPEG2000, MrSid and Djvu), image capture, image assessement and history.
Some metadata are automatically captured, by both scanner and camera. Others must be written manually.
Most metadata are part of the digital object, mainly those of interpretation and preservation. Those relating copyright are not included.

It is aimed at all those involved in digital archiving.

Link to the dictionary: