PS - I had thought it was copper oxide that made the Pullman Green, too, but
Arthur Dubin in Kalmbach's Pullman Painting Guide said that Pullman combined
the yellow of rural dirt with the black of the industrial areas to make the
color, which would suggest a combination of raw siena and raw or burnt
umber. While the patina of copper certainly is stable, I don't recall any
jade green paint shade being common until the late '50's, when again
something must have made it possible.
- John Nehrich