A surprising result: With Tmax-100 (TMX), D316 acts like a compensating developer. Here's the graph of D316 and XTOL:


Compared with XTOL, D316 has (1) a slightly higher toe (giving a bit higher film-speed), (2) same midtones, and (3) compressed highlights. With most films, D316 gives the same or higher shoulder; with TMX, the shoulder is lower and sooner. While helpful for high contrast scenes, this is supposed to be a general purpose developer. The leader density is also lower (2.11 vs 2.28).

Any idea why this happened? I believe that compensation occurs due to either a drop in pH (poor buffering) or developer starvation. D316's buffer/phenidone ratio is better than XTOL. Its AA/phenidone and sulfite/phenidone ratios are similar, so why would the phenidone be starving?

Is this simply a case of underdevelopment?
Would multiplying the amount of both sulfite and concentrate by 1.5x or 2x help?
Or perhaps boost the sulfite in order to boost pH closer to 8.2?

Mark Overton

@Bruce: When I'm done with Tmax-100, I'll test Delta-100.