Adding a dash of color tint to a black and white photo can often produce a dramatic effect, and digiKam does have a handful of toning filters for you to try.
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.