Dick Z. wrote:
James, I beleive the color was added to 3 seperate negatives taken with 3 basic filter colors then each dyed with one of the three basic colors then overlayed to make the color print. That process is probably used today and now called the dye transfer proccess. I'm not sure who invented it but I've seen super salon prints made by that process.
Perhaps you could Google the Die Transfer print proccess and find more on the subject.