I have some experience now creating solid DCP profiles with Ander Torger’s great DCamProf command line tool.
Now my idea is to create a common or film material specific profile for black and white or color negative film by capturing an IT8 target on film, digitizing it and then use the common procedure to create a profile.
For a black and white film this is usually not necessary because inverting the tone curve is sufficient and may keep more film-specific tonality. Anyway, I want to know if it works. To start I have captured a black and white negative (AgfaPhoto APX 1000), exactly cropped the target in RawTherapee and then used “save reference image”.
scanin -v -a -dipn target.tif it8.cht R170830.txt
scanin will have problems with
-p, if the target is a negative image, so use
-a and have a close look at the diag.tif afterwards.
dcamprof make-profile -i D50 -I D50 -S -x ./exclude.txt -r './negative.json.info' -n 'Nikon D5200' target.ti3 './negative.json'
By intention I use the same illuminant as the target was measured, because it’s b&w.
exclude.txt must contain patch names of all colored patches, so only the last row with the gray patches is left.
dcamprof make-dcp -t acr -H -n 'Nikon D5200' -d 'AgfaPhoto APX 100, DisplayLGENexus5X,-i D50 -I D50 -S,-t acr' -c 'Andreas Kalsch' './negative.json' 'Nikon D5200 AgfaPhoto APX 100, DisplayLGENexus5X,-i D50 -I D50 -S,-t acr.dcp'
-H will suppress the hue shift discontinuity error which will happen in this case.
dcamprof test-profile -i D50 -I D50 -S -r './negative.test' target.ti3 'Nikon D5200 AgfaPhoto APX 100, DisplayLGENexus5X,-i D50 -I D50 -S,-t acr.dcp'
But neither the gradient images dcamprof creates under negative.test/ are inverted (colors are just lightened up and paler), nor does the resulting DCP cause an inverted image in Lightroom or RawTherapee.
I guessed that this probably won’t work. Is there any trick to make this is possible?