In the DK-93 formula on this site, it is stated that Kodelon was paraminophenol hemioxalate. Other sources, such as Anchell's The Darkroom Cookbook call for paraminophenol hydrochloride. Understand that I'm working at or beyond the limits of my chemistry knowledge. The formula weight of paraminophenol hydrochloride is 145.6, and it has one phenol ring. I calculate the formula weight of paraminophenol hemioxalate as 320, with two phenol rings. So we would conclude that two molecules of the hydrochloride version compares to one molecule of the oxalate version, so to convert the 5 g of paraminophenol hemioxalate to paraminophenol hydrochloride, we would multiply by (291.2/320) and get 4.6 g. I'm tempted to round that to 5 g and say the two salts are interchangeable. Does anyone know if I did that right? Thanks.

I'd say that you could use EITHER 5 grams of paraminophenol HCL, OR 5 grams of paraminophenol Base as replacement for the 5 grams of Kodelon called out by the KODAK Formula (Published in the KODAK Data Book on FORMLAS AND PROCESSING, Third edition). BTW, Kodak identified Kodelon as paraminophenol OXALATE (1928). Where does Anchell call out paraminophenol HCL in the context of a DK-93 formula? I can't find a reference.

Anchell printed the DK-93 formula in The Darkroom Cookbook, 2nd ed., Formulas chapter, Universal Developers section, page 207.

Interesting, there is no DK-93 formula in either of the The Darkroom Cookbook versions I own. In any case, DK-93 is a Kodak formulation and not an Anchell formulation. The pertinent Kodak documentation states that Kodelon is paraminophenol oxalate. Oxalic Acid is a reducing agent in its own right, as are its salts and its anion (Oxalate).

Just substitute an equal amount of paraminophenol hydrochloride for the Kodelon. The molecular weights of the two salts are close enough for such a substitution. BTW, Kodelon is the hemioxalate salt since oxalic acid has two replaceable hydrogens compared to hydrochloric acid's one hydrogen.