Hi Ron,
This is a step I often do to darken the background on planetary images including images of the Ice Giants and particularly images taken in daylight or bright twilight, often Mercury or Venus. I would always do this after wavelet processing as the application of the wavelets will change the histogram distribution quite markedly. You won’t lose planetary data unless it is something very dark like the Crepe ring on Saturn. Removal of the background like this is a simple way of boosting the contrast.
Martin