## D-23, Microdol-X, D-76: Curves, Sulfite, etc.

I have read that D-23 (not divided D-23, but D-23) is basically the same formula as Microdol-X. In these formulas, the main developing agent is Metol, while D-76 contains Metol and an additional developing agent, Hydroquinone.

They all rely on a considerable amount of Sodium Sulfite.

Do these developers produce an S-shaped densitometric curve with most films ? If so, why ? Does D-76 produce a more linear curve than D-23/Microdol ? If so, is it because of Hydroquinone ?

Compared to traditional films, are T-grain films less compatible with developers like these, which rely on Sodium Sulfite ?

Does the curve become more linear as theses developer are diluted (1:1, 1:3) ? Is that due to local exhaustion of developer ? If so, does that suggest that too much agitation reduces the compensating effect, and thus negate the benefit of dilution ?

Do these developers give lower film speed than other developers, which they trade for finer grain ?

I ask because I have been attracted to the simplicity of D-23, which has only 2 ingredients.