[Neanderman]

a more polydisperse emulsion with coarse and fine grains lower(s) the contrast

IOW, given that the characteristic curve is essentially a distribution curve, the wider the range of sizes, the lower the contrast and the shorter the range, the higher the contrast. Or, stated more simply, if all of the crystals were of the same size, you would have an extremely high contrast emulsion that would essentially be a straight, vertical line.

Correct?

Ed