REMOVE

1. Photographs
2. Horseback riding.
3. negative
4. Portrait photographs
5. Library of Congress Prints a …
6. Unknown

WHAT

1. Acetate negatives (1)
2. Horseback riding. (1)
3. Portrait photographs (1)

WHO

1. Library of Congress Print … (1)

WHEN

1. 1911 (1)
2. 1942 (1)
3. between 1911 and 1942 (1)