Using tools available in digiKam, you can simulate a number of effects, including bleach bypass. This effect produces a desaturated high-contrast image. Creating the bleach bypass effect in digiKam is done in two simple steps.
This is a companion discussion topic for the original entry at https://www.digikam.org/news/2013-04-02_create_a_bleach_bypass_effect_in_digikam/