REMOVE

1. autochrome
2. Autochromes
3. Rainbows.
4. National parks & reserves.
5. Library of Congress Prints a …
6. 1869-1942

WHAT

1. Canyons. (1)
2. Landscape photographs (1)
3. National parks & reserves … (1)
4. Photographs (1)

WHO

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

WHEN

1. 1906 (1)
2. 1912 (1)
3. between 1906 and 1912 (1)