I have been mixing my own RA-4 print developer with reasonable results. However, I find that an awful lot of papers tend to have a cream base because of base fog. It seems that because RA-4 paper is so much more sensitive than the old RC-74 stuff, it does tend to pick up a bit of base fog. The formula I am using calls for an optical brightener, Tinopal SFP, but I understand there are also many alternatives to this. I don't have such a chemical, and I believe it would make my prints more "punchy" by whitening the base. My question is: Does anyone have any idea where a modest or small quantity of such a brightener may be obtained? I am completely stumped.....hours spent on Google have not helped, unless I want to order a truckload from China.