This nondescript image is of a building in Tacoma WA on an overcast afternoon. I converted to B&W by changing the SPP software's White Balance to MONOCHROME. Then I fiddled with the sliders, contrast, exposure & highlights until I liked the way it looked on my monitor. Finally I tried different amounts of Fill Light, both positive and negative.
The positive fill light image (a lot of fill light) is reminiscent of HDR images with a great deal of light smoothing. The negative fill light is interesting, harder to describe. It seems to bring a bit of smudge vignetting quality. This will require more trials. At first it put me in mind of old B&W movies.