The National Archives Catalog


Base

Mandatory Repeatable Data Type Authority Level Available A/V Only Public Element
No No Variable Character Length (60) Base List Item No Yes
Definition:

The substance of the media used to physically carry or hold the information in the archival item. Also called the substrate.

Purpose: Provides the physical characteristics of the archival materials, which helps establish conservation, storage, retrieval, reproduction, and use requirements.
Relationship: This element is dependent on Specific Media Type. Each media occurrence of the archival materials must have a specific media type specified to create Base.
Guidance:

Choose an appropriate term from the Base Authority List.

The base for textual records on traditional media can be fabric, vellum, or paper. The base for textual records on electronic media can be cellulose acetate or polyester for magnetic tape or metal for optical disks. For magnetic video and sound recordings, the base is usually cellulose acetate or polyester, which has sufficient magnetic coating to hinder print-through. For non-magnetic sound recordings, the base can be shellac, vinyl, or wax used to make discs or cylinders that contain grooves to carry the audio information. For motion picture films, the base is the transparent, flexible support (usually cellulose acetate or polyester) on which photographic emulsions are coated to make photographic film. For printed photographs, the base can be paper or, more specifically, resin-coated or fiber-based paper. For negatives, the base can be glass or polyester (film).

Be sure to indicate the base whenever it serves a distinguishing feature for the specific media type, as is often the case with special media records.

Use Media Occurrence Note to include any additional information on the base.

Examples:
Photographic Paper: Resin-coated
[For the prints in the series "Kenneth Space Photographs of the Activities of Southern Black Americans" which consists of two specific media types: prints and negatives.]
Cellulose Acetate
[For the negatives in the series "Kenneth Space Photographs of the Activities of Southern Black Americans" which consists of two specific media types: prints and negatives.]
Paper
[For the series "Warden's Notebook Pages," which was written on loose-leaf notebook pages.]


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