Can I automatically adjust a histogram?

Processing
5

Yes, if you can work out what the formula is. I guess you are moving the end-stops inwards a bit beyond the current min and max values, so you get some clipping at both ends.

For example, with ImageMagick:

magick in.tiff -contrast-stretch 2x3% out.tiff

This clips 2% of pixels values at black and 3% at white.

magick in.tiff -level 2x97% out.tiff

This increases contrast so what was 2% becomes 0%, and what was 97% becomes 100%.

magick in.tiff -level %[fx:minima*100+2]x%[fx:maxima*100-3]% out.tiff

This increases contrast so what was 2% above the minimum becomes 0%, and what was 3% below the maximum becomes 100%.

If your formula creates values less the 0% or more then 100%, there are methods to bring them back into range, while keeping some detail at both ends.

Once you have a formula you are happy with, a shell loop can do all the images in a folder.

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