REMOVE

1. Horseback riding.
2. Nitrate negatives
3. Library of Congress Prints a …
4. between 1936 and 1942

WHAT

1. Horseback riding. (1)
2. Nitrate negatives (1)
3. Photographs (1)
4. Portrait photographs (1)
5. negative (1)

WHO

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

WHEN

1. 1869-1942 (1)
2. 1936 (1)
3. 1942 (1)
4. between 1936 and 1942 (1)