Not being "small", I post it here standalone.
This comes from a long-lasting implementation. Issabella -who was deeply involved in stepped testing phases- knows the history very well...
The filter makes use of a series of steps. If you run it with defaults you see all the steps on the many layers generated (by default the image is not flattened).

Just one example.
original

with and without option "WhiteBalance"

Super!

Original:

Without ACE and without whitebalancestretch

With only whitebalancestretch2

With ACE and whitebalancestretch2:

Thanks, iarga !

Thank you so much Dinasset. You deserve a huge prize for your effort and determination.

It's magic!

Huge thanks, Issabella, both for the many many tests you did on my endless versions and for these nice contributions.

You got it, my friend.

It's so effective.

Thanks Issabella.
Just one warning on its use: because the filter tends to exaggerate the effects, it's often useful to merge the results with the original (run the filter with size = 0, then move it on top of the original and play with opacity)

Thank you so much Dinasset for your smart advice. Much better results.

Continue playing.