StaffGuide: CONTENTdm Cookbook

Recipes for Metadata Entry for the University of Arkansas Libraries


Field Name: Extent is the default. However, custom-tailored field names (Dimensions, Duration, etc.) may be appropriate for an individual collection.
Requirement: Optional
Repeatable: Yes
Search: No
Hide: No
Vocabulary: No
Dublin Core (DC) Mapping: dc.format.extent
MARC Mapping: 300 $a (pagination or duration); 300 $b (illustrations); 300 $c (dimensions)
CONTENTdm Data Type: Text
Dublin Core Definition: The size or duration of the resource.
UA Definition: The size or duration if deemed important for description of the resource.

While the Digital Format element is required and uses controlled vocabulary, this optional element may be used to record additional information about the resource. Common uses would be to give the dimensions or number of pages of the original physical object being digitized or the duration of an audio or video file.

When the Extent element is being used in a collection that contains multiple kinds of resources, prefer separate Extent elements along with clarifying element names for each type of resource. For example, in a collection that contains both images and sound recordings, it would be appropriate to use name “Physical Description” or “Dimensions” for the former and “Duration” for the latter.


  • 2-D objects on individual sheets. When the original item is a standard trade size (for photographs 3 ½ x 5, 4 x 6, 8 x 10, etc. and typescripts 8 ½ x 11, 11 x 14, etc.), give the dimensions as such, followed by the designation “inches.”  Otherwise, record dimensions in inches and enter in format: [height] x [width] (that is, separate each number by a space, lowercase x, space), followed by the designation “inches”. Round up to the next ¼ inch.


  • Books and bound objects
    • Record the height of the volume.
    • Give in centimeters followed by the designation “cm” (no period). If the volume measures less than 10 centimeters, record the height in millimeters and use the symbol “mm” (no period).
    • If the width of the volume is either less than half the height or greater than the height, record the dimensions as [height] x [width] (that is, separate each number by a space, lowercase x, space).
    • Round up to the next whole centimeter. 
    • If also recording pagination, pagination should precede the dimensions and be separated from it by a space semicolon space. Give the number followed by a space and designation “page” or “pages.”  For example:

      479 pages ; 31 cm

    • If recording pagination and information about illustrations, give as follows:

      307 pages : illustrations, portraits ; 32 cm

  • 3-D objects. Record dimensions in inches and enter in format: [height] x [width] x [depth] (that is, separate each number by a space, lowercase x, space), followed by the designation “inches”.  Round up to the next ¼ inch.
  • Use judgment when deciding to include dimensions for other types of original objects.



Enter a duration (playing time) using the applicable time elements from the W3CDTF format, separating each element with a colon. The format is as follows:

hh = two digits of hour (01, etc.)

mm = two digits of minute (00 through 59)

ss = two digits of second (00 through 59)

However, omit any element that is “00” (provided that no placeholder is needed).







File Size

A separate “File Size” element may be included when the subject selector wishes to provide this information for one or more digital objects in a collection. Likely candidates are large audio-visual or PDF files.

Use of the “File Size” element should be discussed during the initial project team meetings. The Digital Services Department will record this information for the agreed upon items in the metadata spreadsheet.

The format is number of units followed by the appropriate size designation (MB for megabytes, GB for gigabytes, etc.). For example:

130.7 MB


3 1/2 x 5 inches

434 pages ; 29 cm

18 x 34 x 26 inches

Revision Date: 10/23/19