(05-25-2020, 03:53 PM)ajax Wrote: Maybe I posted this question in the wrong forum.
My assumption is that "Auto" means to algorithmically do what the user could have done by manually exercising the various controls. If so it would be most helpful to display the results in the dialogue window in the various display areas that get updated when the controls are exercised individually be the user.
This is exactly what you see if you hit the "Auto input levels" followed by "Edit these settings as curves". AFAIK it stretches the inpiut values so that in each channel the top X% lighter pixels are 255 and the top X% darker are 0, in other words it drags the left and right input handles until they touch the histogram. The problem is that this can induce a color shift. In a picture with a blue tint, the highest "red" may be around 128, so all light pixels are blue/cyan, and after auto-levels the highest red will be 255, as will be the green and blue, so the lighter pixels are now white.
(05-25-2020, 03:53 PM)ajax Wrote: Might it make sense to be able to save a good result as a preset?
No... because that's the point of "Auto". It is computed for the image at hand. What is good for one image would not be good for the next. If you really want to save settings, you can go to the Curves dialog as indicated above and save these settings
(05-25-2020, 03:53 PM)ajax Wrote: Also, while good, sometimes the algorithm "over does it" just a bit and the user ought to be able to tweak it just a bit. The way I'm doing it produces no clue about what was done that may have been a pretty darn good place to start.
In he Curves dialog you can fix this.