Indexing conventions usually prescribe that the most specific term be assigned to the material being cataloged. The choice of terms also depends on the use of the collections, the degree of available information, the relationship of the material being cataloged to the rest of the institution's holdings, staff expertise, and whether the catalog record represents a single item or a group of items. Decisions about the level of specificity should also take into account the needs of a growing manual file or local automated database and the possibility of contributing records to a multi-institutional database, or other modes of record distribution.

If uncertain of a specific physical process, assign a broader term. Although terms are available for use when a process is recognized, one should not feel compelled to try to identify every process as specifically as possible in every case. Example: When a color photographic print process cannot be easily identified, PHOTOGRAPHIC PRINTS--COLOR may suffice.

In accordance with conventional subject indexing practice, a narrower term and its broader term should not both occur in a record for a single item. However, for a group, it may be appropriate to assign both broader and narrower terms. Example: An aquatint is indexed with: AQUATINTS. The additional broader term INTAGLIO PRINTS would be superfluous.

Example: A group that contains mostly cyanotypes, but also has a scattering of many other photo processes, may be indexed with: CYANOTYPES and the broader term PHOTOGRAPHIC PRINTS.

Conventional indexing rules prescribe use of the broader term when more than three of its narrower terms would be headings in the catalog record. The desire for access to examples of specific media and genre in a group may call for deviation from this practice and use of all the terms. When, however, the specific aspects are considered too numerous to index separately, either in a group or single item, the practice of using the broader term should be followed.

Example: A group containing a photographer's work includes mostly platinum prints but also has a few cyanotypes and tintypes. Each type is indexed because it is important to highlight them all in the context of the institution's holdings.

Example: The kinds of ephemera in a scrapbook are too numerous to index separately. The general term EPHEMERA is used.

Example: A drawing includes graphite, chalk, and crayon, and no one medium predominates. The general term DRAWINGS is used.