Don't know if that's possible, but would be a nice addition: being able to adjust the effect of the several "automatic color adjustment" tools (automatic exposure, expand contrast... [translated from German version]) Often the desired result lays somewhere between the original and the applied effect. So my current workflow is: apply the effect, save it as "Version 2", opening original in Gimp, putting Version 2 as a layer over it and reduce the opacity of Version 2-layer, so that in the end I have a "mix" of both versions, in other words: applied the effect only a little bit. If I could reduce the effect directly in digikam with a slider that would be fantastic and save me a lot of time :-)
*** Bug 451783 has been marked as a duplicate of this bug. ***
See the GmicQt tool for Image Editor who provide plenty of filters where adjustements are available. See the online documentation for details: https://docs.digikam.org/en/image_editor/enhancement_tools.html#g-mic-qt-tool Gilles Caulier