RGB adjustements highly non-linear

[oayz]

May not be a bug but a feature In RGB ajustements:

0-50 basically make no effect, somewhere around 70 it starts to actually adjust color, around 100 become visible:

Here is the example:

R, R_agjust, new_R:

64, 0-50, 64 (no change !!!)
64, 0-60, 65
64, 70-80, 66
64, 100, 67
64, 120, 70
64, 140, 75
64, 160, 79
64, 180, 86
64, 200, 94
64, 220, 104

Adjustment curve is highly non-linear and not as expected. Normally we either increase RGB by %% ( +/-100%) or by value (+/- 255)

BTW, I believe it's a regression for quite a few releases

[user0]

it has been changed in 181

yep, some adjustments are welcome

• calculation
  - revert calc to the one from 180 for RGB sliders in Enhance colors
  Color balance in Batch convert works as expected

• scale's UOM
  - maybe change scales to % (w/o % indicator) for Brightness/Contrast, RGB, Hue, eg like in Affinity/Ps
  Percentage scale seems more intuitive and I just don't see advantages of using an integer scale (255 and 127 (255/2)).
  
  Example

  

  instrument_ranges.png (32.11 KiB) Viewed 29 times

[xnview]

Thanks to your detailed description I can reproduce the problem.