PiezoDN is available as a $75 purchase. It gives you a set of tools (including the curve adjustment tool), dig neg curves, as well as workflows, targets, and access to a private support forum.
Can you explain or update me on the availability of a “curve adjustment tool”? It seems to only be part of a package that one uses for making Digital Negatives. I would really use it to make an altered curve to print better dark tones on my 4880 using Selenium/MKUHD. Results on Canson RP and it’s appropriate HD curve are looking weak and lacking separation in the darks (85-95%).