Can these measurements be treated as arithmetically in the sense that if you just wanted to “zero out” (i.e. ignore) the (non-) whiteness of the paper, you could subtract (100-maxValue) from each reading?
With negative densities, it is/was common to subtract the (film) base + fog density from readings. So you might try to expose and develop for a Zone I density of “0.1 above base+fog”. If base+fog (i.e. unexposed but developed
film) measured 0.2, then the target Zone I measurement would be 0.3.
Myron
On Mar 8, 2019, at 10:41 PM, richard@richardboutwell.com [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
What you are after is a basic normalization formula, but I don't think it will make a difference for the linearization. If you load your measurements into the A column in a spreadsheet, paste this into the B1 and drag down for the whole column.
=((A1-A$21)/($A$1-$A$21))*100
basically it is (value / minValue) / (maxValue - minValue) which will give you 1-0 and then multiply by 100 for 100-0
93.9321 100 91.4298 97.098574 88.1817 93.3323903 83.4927 87.8954777 78.2883 81.860957 71.3222 73.7837387 65.4938 67.0256876 60.6404 61.3981527 54.9781 54.8326952 49.7342 48.7523741 44.4122 42.5814957 39.0966 36.4180382 34.6358 31.2457243 30.5362 26.4922232 26.4416 21.7445196 22.1175 16.7307099 19.0314 13.1523657 15.7048 9.29516093 12.0409 5.04685554 9.378 1.9592133 7.6883 0