Should the mask adjustments in tone equalizer be improved

Software darktable
61

Terry is right, I meant the controls on the masking tab to pick exposure and contrast.

62

I wonder if it a bit of push pull going on…ie is the result of one impacting the other. I have gotten used to just clicking back and forth a couple or 3 times and it end up centered usually… so essentially offering iterations…

63

That was my idea as well. Only controls that directly affect the histogram should be in the advanced tab.

64

It’s not an interplay between contrast and exposure. See how the value changes between -0.84, -0.85 and -0.86 (I keep clicking the exposure compensation ‘magic wand’):


Also for @rvietor.

65

I couldn’t make them work on my windows computer V4.7. Short cuts like that sound a nice idea.

66

I barely looked into it, but I think this is what the auto is doing.

#define CONTRAST_FULCRUM exp2f(-4.0f)

  // calculate exposure correction
  const float fd_new = exp2f(g->histogram_first_decile);
  const float ld_new = exp2f(g->histogram_last_decile);
  const float e = exp2f(p->exposure_boost);
  const float c = exp2f(p->contrast_boost);
  // revert current transformation
  const float fd_old = ((fd_new - CONTRAST_FULCRUM) / c + CONTRAST_FULCRUM) / e;
  const float ld_old = ((ld_new - CONTRAST_FULCRUM) / c + CONTRAST_FULCRUM) / e;

  // calculate correction
  const float s1 = CONTRAST_FULCRUM - exp2f(-7.0);
  const float s2 = exp2f(-1.0) - CONTRAST_FULCRUM;
  const float mix = fd_old * s2 +  ld_old * s1;

  p->exposure_boost = log2f(CONTRAST_FULCRUM * (s1 + s2) / mix);
67

I just click one then the other and then back and forth usually if it is not right in one cycle a second cycle or usually at most a 3rd one will end up with the mask centered and expanded as much as it can given the image…

68

@g-man with each weekly build on Windows I jump straight to the tone equalizer looking for your new improvement to the advanced tab. I hope this idea is still on the cards for 4.8. because your proposal looked great.

69

It did not worked out. I’m still thinking of options.

70

Good luck because the idea is both brilliant and needed.

71

There is code that is part of the lua script for the initial workflow script and one option in that script is to enable the pickers so that when you open the tone eq the mask is centered… I haven’t used it for a while but it seemed to do a good job… That module had a ton of options and could be slow but if that part of the code works more consistently than what happens from within the module then maybe it could point to an improvement in the code…

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72

I stopped using it because it was too slow for me.

73

Ya I think its slow to do all the things it does but if it could just do one or two key sub functions then it might be quicker ….

74

I have found that while it may seem habit to do the top slider first… go the other way click the contrast one first then exposure… I think the hit rate for a centered result is much better…

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75

I am still keen on the idea of the sliders being in the advanced tab but I wonder if another option would be to replace the current display in the masking tab with the histogram?