I was lucky enough to be able to visit 31 Studio platinum printroom yesterday, they said that the developer has the greatest influence on the tone in the print rather than the ratio of pt to pd. I have ammonium citrate which produces cool tones with arches platine and apparently the opposite with aquarelle. Considering I would like a warm tone to my prints it was suggested that heating up the developer could make a difference. Would the ammonium citrate heated to 40 degrees, the highest my water bath will go yield a warmer print. Also, I was looking at the prints they made of Coburn's work which im sure they referred to as gumover but a mention of vandyke brown also came up when talking about them, whats the difference in the processes? Thanking you kindly!