The photographs and microfilm in the Music Library collections provide original research material that documents the history of music, musical instruments, and the lives, work, and personal relations of musicians. Holdings provide secondary sources in the form of musical iconography; there are also copies of rare or unique research material otherwise unavailable locally. The black-and-white gelatin prints of the Plaut Columbia Studio Recording Session collection are the largest group; there are also albumen and color photographs, and some 11,600 reels of microfilm.

The photographs in the collection are part of larger research collections, which include photographs in archival papers of composers and musicians, microfilm of rare and manuscript musical sources from European libraries, and files of musical iconography of musicians, musical instruments, and musical performances. The collections are international in scope and date from the 19th century to the present. Many are unique, others may be duplicates but difficult to locate elsewhere.