I tested D400 in Xtol 1:2 and got a true speed (0.1>B+F) of 400. While it will get the published EI, the fog is a little too high for my tastes. I recommend diluting Xtol at least 1:2 to avoid the unpleasant softening effects of the solvent action of undiluted Xtol.(posted 8771 days ago)Using PMK, the true speed is 250, 2/3 of a stop less, but with a dramatically superior result. The HD curve is nearly a straight line with no highlight blocking.