[Alt-photo] Digital negatives help?

Niranjan Patel nirpat89 at yahoo.com
Mon Sep 26 00:43:02 UTC 2016


Don:
This post should be in the thread started by Henry Rattle with the same subject line but I just (re)joined the group so I don’t have the previous e-mails.  
In any case this is regarding the King/Harris technique you suggested to Henry to get a higher Dmax from a digital negative.  First a background.  I have been meaning to take up all these wonderful alt-processes for a while now and had even joined this group for a short period almost a decade ago (when I was still battling my inevitable succumb to the digital camera and Photoshop) to learn from the great wealth of knowledge that is available here for the taking.  Around that time I had bought a box (unknowingly perhaps one of the last ones) of Chicago Albumin’s POPs, which sitting in the my refrigerator all this time were found to be amazingly still pretty good when I tested recently   So I thought I will use it to ease in to the world of alt-processing by just focusing on the digital negative and wet-processing without having to deal with coating rods and blooming gelatin.  Ultimately, when I run out of POPs, I want to go on to Pt/Pd and that poor man’s Pt/Pd - the salt printing. 
I am using ChartThrob, an old batch of Pictorico OHP Premium Film and HP 9180B (another dinosaur that won’t quit.)  At first I used the composite black printing mode to learn the conversion curve (which incidentally is pretty steep.)  Things looked good but the white point could barely make it to an RGB of 205 or so on my scanner.  The unexposed paper processed in the similar fashion (fixed in plain hypo and toned in Kodak Rapid Selenium Toner) went as high as 240 or so.  So I did the colorizing tests where I varied R and G in 5% steps in an 11x11 matrix (I didn‘t want to bother with B at this point assuming B will be much more transparent than the other 2.)  The result of that was indeed a better colors for a higher white point, the best being around R/G/B of 51/128/0.  Now the 255 square (0 in the negative) is reading about 225, much improvement -specially to the eye.  
Now I am greedy so I was looking for some other way to boost it even more.  In comes your advise about adding a black fill layer that I promptly wanted to try.  I did that on the ChartThrob 101 squares matrix with a Green layer of 51/128/0.  Here is what I find:
After putting in the second fill layer and changing the blend mode to Multiply and changing the blending options for the lower Green layer and the opacity somewhat close to the numbers suggested, I end up with the square 0 in the negative to be, for example, R/G/B of 16/41/0.  With B still being 0, this is still within the 11x11 matrix I did before where the best square was found some where else.  
So the question is this:  Am I doing something wrong in putting together the layers or in my analysis.  I am pretty sure at 16/41/0, it will end up darker than what was already achieved at 51/128/0.
Sorry for the long-winded note.  And Hello to all on the list.

:Niranjan.
http://niranjanpatel.zenfolio.com/





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