Peter, I have lost the exact patent reference. I spent some time trying to find it again, to no avail. Here is where I started:

http://patft.uspto.gov/netahtml/search-bool.html

My search criteria were; negative film, Eastman Kodak, and processing but the number of patents is truly amazing for some searches.

Since I really don't mix anything but Blix, Bleach and Fix for color, I just never held on to the developer formulas.

PE