When an image depicts recognizable types of graphic materials, a genre or physical characteristic term may be used as a topical heading (MARC field 650). The genre or physical type shown in the picture is its subject.

Example: A newspaper engraving of a family viewing stereographs is indexed with: PERIODICAL ILLUSTRATIONS (655), WOOD ENGRAVINGS (655), and STEREOGRAPHS (650).

Example: A stereograph of a family viewing stereographs is indexed with: STEREOGRAPHS (655) and STEREOGRAPHS (650).

Example: An engraved self-portrait of an artist making a self-portrait is indexed with: SELF-PORTRAITS (655), ENGRAVINGS (655), and SELF-PORTRAITS (650).

Occasionally, one genre imitates another, and the genre being imitated becomes the subject.

Example: A cartoon designed to look like a piece of currency is indexed with CARTOONS (655) and MONEY (650).

In anticipation of the need for 655 terms as subjects, all TGM II terms have been incorporated in the Thesaurus for Graphic Materials I: Subject Terms, which is an authorized source for terms in MARC field 650. Only the postable and lead-in terms appear, not the scope notes or full syndetic structure.

For consistency in cataloging, terms are suitable for use in other areas of the record, such as the physical description (MARC field 300) or a note field (MARC field 500). The thesaurus terms may be supplemented in the physical description and notes by uncontrolled vocabulary in order to describe material in greater detail.