Size

The Size field provides the measurement of the item.

Photograph
Photographs are measured in centimeters. The measurements recorded are Width (W) x Height (H). An example is 12 x 8 cm.
If the photograph is in a frame the measurement would be Width (W) x Height (H) x Depth (D).

Book
The number of pages is used as the measurement for a book used for information rather than as an object. Example could be 210p or 18p. The number of pages indicate not only the size of the book but also helps a researcher determine the amount of information available on the topic.

Map
Maps are measured in centimeters. The measurements recorded are Width (W) x Height (H).

Audio visual items
The size is recorded in minutes when this is known