Let me be rephrase my comment. Too many variables affect photographic paper's D-max to make reflection sensitometery reliable in choosing the contrast level of a printing paper in my darkroom.
I did not mean to indicate the instrument was mechanically unreliable, but the results cannot be relied on to give useful information in my printing technique.
Ok, try this. Make a test strip that goes to maximum black on the paper but keep blasting it with additional strips of exposure. Lay the processed and dried paper on an opaque surface and check for the darkest strip, now hold it up to the light. You can now see all those darker bands. So, even how you hold a print to view it influences D-max. Let alone effects of toning, print drying technique, angle of viewing, etc. To rely on reflection sensitometer results for choosing paper grade, all that has to be taken into account. I'm not saying that all can't be done. Just that I use my eyes to zero in on the correct exposure and filtration when making a print.
Last edited by ic-racer; 10-22-2012 at 10:33 AM. Click to view previous post history.