A concentrated, Phenidone-only developer (J. D. Kendall)
I find this interesting as it is the only developer I know of other than POTA using only Phenidone as a developing agent. The patent by Kendall (U.S. Pat. 2,289,367) is from 1942. My source for the formula is Modern Photographic Processing by Grant Haist (vol. 1, Special-Purpose Developers, Concentrated Developers, p. 523).
3g 1-Phenyl-3-pyrazolidone (Phenidone)
25g Sodium sulfite (crystalline)
50g Sodium carbonate (crystalline)
0.5g Potassium bromide
500ml Water to make
Dilute 1+3 for use.
Depending on the hydration state of the sulfite and carbonate available, the following ratios can be used:
-For anhydrous sulfite, multiply the crystalline amount by 0.5 (= 12.5g anhydrous sulfite in the above formula)
-For anhydrous carbonate, multiply the crystalline amount by 0.37 (= 18.5g anhydrous carbonate in the above formula)
-For monohydrated carbonate, multiply the crystalline amount by 0.43 (= 21.7g carbonate monohydrate in the above formula)