Having as background that Parodinal (or Rodinal) is a weak color developer, I had the idea of giving it a push with the right color developing agent CD4. I replaced a part of the para-acetylaminophenol, aka Paracetamol or Thylenol, in parodinal with CD4 in order to make a multipurpose developer for both color (C-41) and B&W.
The results are until now very promising. I developed a color roll in dilution 1:100 for one hour and the same with a B&W film. See pictures below:
In this dilution, 1:100 it is a good B&W developer. The C-41 film gave unsaturated colors and a shift to magenta. I will try to make it better. I didn't use temperature, I developed at room temperature, and the dilution is for color perahps too weak.