Version: 0.10 (using KDE 4.2.3) OS: Linux Installed from: SuSE RPMs Since the value channel shows the largest differences in terms of brightness, it is useful to use it for sharpening an image without touching the hue or saturation. I'm not sure this is useful for other tools as well, but digikam could provide the facilities to automatically create a hsv temp file while the user adjusts the tool and write that temp file back if the user saves the changes. That way the user can pick the channel the tool should work on while editing a picture without any knowledge about conversion to hsv etc.
Currently an option for "Suppress color noise" is added to unsharp masking if the checkbox is selected the filter is applied on luminosity(value) channel only, is that sufficient?
The Image Editor GMIC-Qt Details/Constrained Sharpen allows to use plenty of color spaces other than RGB* and apply changes on a dedicated channel. https://i.imgur.com/M5LCPBi.png Gilles Caulier