REMOVE

1. Portrait photographs
2. Photographs
3. Acetate negatives
4. Library of Congress Prints a …
5. not before 1918

WHAT

1. Acetate negatives (1)
2. Dancers. (1)
3. Portrait photographs (1)
4. negative (1)

WHO

1. Genthe, Arnold (1)
2. Library of Congress Print … (1)

WHEN

1. 1869-1942 (1)
2. 1918 (1)
3. 1920 (1)
4. not before 1918 (1)