During my Sunday morning ruminations, I re-stumbled across this thread, decided to give it a go. I thought up-front the haze would be too much for my simple rawproc program, but the effort would be instructive. Well, it turned out to be very instructive, so I thought I’d post screenshots of the successive manipulations.
First-off, since I don’t have @Dario’s camera profile, I opened the raw in rawproc with the dcraw equivalent “-o 4 -g 1.8”, which converts the adobe_coeff assigned raw to dcraw’s ProPhoto, and applies 1.8 gamma. The relevant rawproc properties are:
Here’s the screenshot showing that result:
The histogram is telling; the blue channel is definitely shifted right across the entire tone range. I messed a bit with shifting it with a blue curve with the data in this range (63-151 in the 0-255 scale), but the curve was so slight, so I “contrast-stretched” the data with a blackwhitepoint:
This is just like applying a RGB curve with the bottom (black) point scooched to 63 and the top (white) point scooched to 151. The blue channel shift is now more evident, and can be dealt with using a “linear” blue curve:
Note I had to move both the bottom and top points to keep the blue channel aligned with the other two.
I hope these screenshots show up in your browsers to effectively show the transforms. What I’m learning out of these exercises is the value of a RGB histogram of the working image.