Don't even bother with the bicarb. 0.8 grams phenidone, 9 grams ascorbic acid, 25 grams borax and water to make a liter will do the job for either film or paper. If you keep your phenidone in a glycol solution, you can mix a batch in just a few minutes. You will probably want to dilute the stock for use. I'll come back when I can give more information.