I managed to mix inks and fill carts!
Now I am stuck at QTR profiling...
I am using Ilford Gold Fibre Silk and I would like to build a carbon profile.
With the first ink ink separation print (ink limit = 100%) PK does not visually increase above 45%.
(perhaps a densitometer could find a tiny difference between 45 and 50...)
Increase from 35 to 40, and from 40 to 45, is small. So I decided to use ink limit = 35% + black boost = 45%.
To me, this looks similar to your HPR-Baryta-Carbon which uses ink_limit=45 + boost_k=53
In the second print I found the following relative densities with the help of the scanner of a multi-purpose printer:
C = 53%
M = 36%
LC = 18.5%
LM = 11.50%
which again is quite similar to your HPR-Baryta-Carbon.
Finally I printed 21step.tif (in the QuadToneRip directory) with the newly created profile. To my naked eye, I see some problems:
1. the light patches are quite light
2. the gradient on top shows some tiny banding
I think I can solve point 2 by increasing the gray overlap, as discussed here: http://www.bwmastery.com/blog/2015/in-search-of-the-perfect-qtr-profile
With gray_overlap = 75, gamma = 1.7 the gradient has no banding and looks smoother (more inks firing at the same time?)
However this makes light patches even lighter and the scanner is not able to distinguish them.
If I keep gray_overlap = 75 and revert to gamma 1, light patches do not get much lighter; patch 95 becomes similar to patch 100.
I am thinking that, if I could "pre-linearize" by eye, the real linearization with my scanner could become easier.
Thanks,
Federico