Recently I shot my first roll of Kodak BW400CN, a chromogenic b/w film. A first experiance in C41 color developer slightly pushed turned out very good at EI 1600, and I wanted to try Caffenol. I'm not a big fan of color film developed in b/w developer, but this BW400CN developed in Caffenol-C-L is as good as developed in color developer. No doubt. This film is ideal for high speed purposes and hybrid workflow. You can push this film a lot and still don't get to much contrast, for the sample image attached here I even had to enhance the contrast in pp. Grain is still very small, almost unvisible with my Canoscan 8800F. The look is very different from other films, probably ideal for taming highest contrasts. The orange mask is very transparent and the base fog very low.
So here's a sample, no masterpiece for sure, but showing the character of the film under very low light conditions at EI 1600, simple average metering with my trusty Canon A1. Developed in Caffenol-C-L semi stand with 0.5 g/l pot bromide, 20 °C, 70 minutes, fixed in regular bw fixer, increased contrast (s-curve) in Gimp.
Best - Reinhold