REMOVE

1. neighborhoods
2. trains (vehicle groupings)

WHAT

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

More 

WHERE

1. New Windsor, Maryland (1)
2. San Francisco, California (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. 1969 (1)
2. 1970 (1)
3. ca. 1970 (1)