Hi Chris,

Yes, I think so, but there's some question as to whether a staining developer of any kind is the best choice for films with a lot of base fog. I suppose a staining developer can still provide a larger density range than a non-staining developer, important if one is printing in a long scale process, but staining the fog will definitely increase printing times, so it's a judgement call. But yes, if you are decided to use a staining developer, one that produces the minimum general stain is the best choice.

Catechol itself is quite resistant to fogging, which contributes to general stain. In catechol developers that produce fog/general stain, it is almost always the secondary developing agents responsible. This is why a catechol developer that also includes phenidone requires a restrainer. Phenidone, and even metol produce fog in a pH environment appropriate for a catechol developer, and provide no benefit to justify this fault. I don't think phenidone or metol are superadditive with catechol, and perhaps not even additive. If you compare developing times for standard dilutions of Obsidian Aqua and Pyrocat HD, for example, you'll see what I mean. Even though OA contains no phenidone, and uses a lower concentration of carbonate, development times for OA are typically shorter than development times for Pyrocat HD at comparable dilutions. How can this be? Well, I don't know, exactly. There's an awful lot of reactions taking place in a Pyrocat HD working solution that are not present in OA, and some must have a braking effect on development. The same is true for Tanol Speed, which contains both catechol, and pyrogallol, along with two other developing agents, and yet development times are longer than with OA, and fog/general stain are higher, too.

In my opinion, catechol developers are not improved by the addition of secondary/tertiary etc. developing agents, and all the other ingredients added to mediate their effects. Simply balancing the concentrations and ratios of catechol, preservative and alkali is all that is required to make a developer that does everything we want one to do, and nothing we want it not to do. All the rest is obfuscation and confusion.