REMOVE

1. landscapes (representations)
2. trees
3. railroad stations
4. silver gelatin
5. 1945

WHAT

1. exterior views (1)
2. forests (plant communitie … (1)
3. mountains (1)

More 

WHERE

1. Lake Louise, Alberta, Can … (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1920 (1)
2. between circa 1929 and ci … (1)