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