This set of index cards appears to be Rosen's only written record of his photographic studies. Rosen noted on these cards, among other information, the photographic methods he used to examine a work of art, and where appropriate, the stage of restoration or cleaning a work was in when photographed. Many cards contain later notations made in an obviously different hand. Most pertain to reattributions, and a few revise the titles of a work. Rosen's original designations were followed in the arrangement of these cards since some of these revisions still do not reflect current designations.
Subseries D. Index cards
Maintaining the attributions and titles recorded by Rosen, regardless of current designations, cards are arranged alphabetically by artist or object, and within each subgroup, alphabetically by title or other description. Works by unidentified artists are filed last.