Quote Originally Posted by henry finley View Post
It would seem to me that the Zone System of development would require a developer that works in a totally linear fashion, which I believe, is why Adams settled on D-23. It is not an Elon-Hydroquinone combo that works in an un-linear fashion. (I use the word linear for lack better word in my personal vocabulary). But I believe my object is understandable. D-76 was the most popular Kodak product, but not necessarily the best at all. Lacking a pound jar of Elon/Metol, and a big canister of sulfite, I'd say the closets thing pre-packaged would be straight Microdol or the Ilford equivalent. I could be wrong, but best of my knowledge, Microdol was an Elon-only product. D-76 did one thing very well--gave a rigorous development with plenty of grain.
Henry, a few things:

1) Adams ultimately settled on HC-110

2) Generalizing about curve shapes based on the developing agents is an incorrect approach. Little can be said about the characteristics of a developer without looking at the concentration of developing agent(s), the concentration of preservative (Sulfite) and the concentration/type of alkali (pH, buffering). As an example, G. Haist (Kodak) created a modified version of D-76 with identical working characteristics (but less capacity) by slightly increasing the amount of Metol (Elon) and omitting the Hydroquinone entirely. D-76 is a fine grain developer very similar to D-23 in practice.

3) Microdol is said to be D-23 with a little less Metol (5g/l rather than 7.5g/l) and somewhere around 30g/l Sodium Chloride. Microdol-X contained at least one extra ingredient - an anti-silvering agent.