Did a round of B&W shots with my converted Pentax K-5 and the Sigma 85mm/f1.4 lens. Although the camera shoots at 630Nm I used a 720Nm lens filter on these to get more contrast and better B&W after conversion. Raw conversion was with Darktable 4.2.1
I did use a bit of an Orton effect on these to add some glow and atmosphere to them.
Modules used in DT 4.2.0:
ImageMagick script used in a bash script: