Originally Posted by
Dave Gooding
Thanks. what sort of range can a film sensibly cover? I did run a series of 20 or 30 test exposures on Ilford HP5 as part of a calibration exercise (to calibrate a sensor against which each unit is checked and adjusted). I measured the negative intensity and plotted it against exposure. It follows an S-curve with a roughly linear region of +/- 4-ish steps in the middle but there are measurable intensity differences between consecutive exposures even at 10 stops away from the nominal, although to the eye these extreme ones have no discernible difference. Would you really operate the film at these extremes?
Bookmarks