Earl's report is interesting.
Pullman painted its cars pre-1900 in the brown color as later used by UPS. I have seen a paint manufacturer's color sample booklet from the immediate post 1900 era that displays both Pullman Brown and Pullman Green.
The Pullman green will look different to the human eye depending on the lighting (bright sun, overcast-day, artificial light); sometimes appearing more green and in other conditions more brown. There was a discussion about the appearance in a posting thread several years ago on the Railway Preservation News (rypn.org) discussion board "Interchange."
Also be aware that the green color used by railroads was not always the same as the color used by the Pullman sleeping cars. The one-time "Associated Lines" UP and SP both used a different green. Santa Fe also had a different green. Some railroads were very particular about the colors and maintained sample "drift cards;" others bought whatever was available.
Brian Norden