Use the optional Medium element to record important characteristics of the physical object being digitized. This field should not be used for describing the digital reproduction.  Moreover, Medium should normally be used in conjunction with the Type (AAT) element.    

This is a free text field, although consistency is desirable within an individual collection. Use standard English-language grammar, capitalization, and punctuation. Spell out words, at least the first time they are referenced, rather than using abbreviations.

When the Medium element is not used in a collection, information about the original physical item alternately may be included in the Description element.

Mixed media on watercolor paper

Pencil

Cover stock

Color plates