The nether regions of white paper: adjective order.

Which is correct?

A) He gave her a white piece of paper.
B) He gave her a piece of white paper.

Intention trumps order:
He ate a large piece of cake. (Means the piece was big.)
He ate a piece of a large cake. (The cake was big.)

However, when both forms are widely accepted as having the same meaning and you have nothing better to do/ need a cure for insomnia, then:

1. Quantity (or number)
2. Quality (or opinion)
3. Size
4. Age
5. Shape
6. Color
7. Proper adjective
   
8. Purpose (or qualifier)

Color comes after size, the size being "a piece", so B is correct.