[ Thanks to Dmitri
Popov for this link. ]
“But you are not limited to the built-in filters: using
digiKam?s editing tools, you can easily tint photos using whatever
color you like. To do this, open a photo for editing, choose Color
> Hue/Saturation/Lightness and set Saturation to -100. This
effectively turns the image into a black and white photo. Press OK
to save the changes, then choose Color > Color Balance. Usen
then the sliders to create the toning color you want. Press OK, and
you are done.”