REMOVE

1. hats
2. sky
3. parking lots
4. windows
5. shadows
6. backdrops

WHAT

1. Information Forms (hierar … (1)
2. Nonobjective (1)
3. North Dakota (1)
4. art critics (1)
5. artists' statements (1)

More 

WHERE

1. New York, New York (1)

WHO

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

Less

WHEN

1. 1947 (1)
2. 1947 April 20 (1)