It might be cheaper to use an essence of Rodinal. The magic of Rodinal is in its concentration and use of p-aminophenol HCl. This formula came from a Air Force photography manual of 1941.

p-aminophenol HCl 7 grams
sodium sulfite (desicated) 50 grams
sodium carbonate (anhydrous) 50 grams
water to 1 liter

It was specified for tropical use on film. No change up to 80 F. Add sodium sulphate above 80 F. Should work for paper as well.