REMOVE

1. bushes
2. clouds
3. hats
4. rubbish
5. after 1961

WHAT

1. Visual Works (hierarchy n … (3)
2. black-and-white film (3)
3. buildings (structures) (3)
4. exterior views (3)

More 

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)

Less

WHEN

1. 1967 (2)
2. 1969 (1)