REMOVE

1. shadows
2. backdrops
3. trees
4. suits (main garments)
5. buildings (structures)

WHAT

1. automobiles (1)
2. banks (landforms) (1)
3. black-and-white film (1)
4. boys (1)
5. branches (plant component … (1)
6. brick (clay product) (1)
7. bushes (1)
8. children (1)
9. coats (garments) (1)
10. exterior views (1)
11. fields (land) (1)
12. forests (plant communitie … (1)
13. freight cars (1)
14. garages (1)
15. hats (1)
16. hills (1)
17. men (male humans) (1)
18. pipes (smoking equipment) (1)
19. plants (1)
20. railroads (1)
21. rails (transit system ele … (1)
22. roads (1)
23. rubbish (1)
24. signs (declatory or adver … (1)
25. sky (1)
26. soil (1)
27. trains (vehicle groupings … (1)
28. utility poles (1)
29. Visual Works (hierarchy n … (1)
30. wheels (components) (1)
31. windows (1)
32. workers (1)
33. wrecks (sites) (1)

WHERE

1. New Windsor, Maryland (1)

WHO

1. Campbell, Sandra L. Still (1)
2. Clyfford Still; Still, Cl … (1)
3. Sandra L. Still Campbell; … (1)
4. Still, Clyfford (1)

More 

WHEN

1. 1969 (1)