Digital BW, The Print

OPM/IJC from Bowhaus uses 16 bit for printing.

I quote from their website:

...All of IJC/OPM profiles and rendering algorithms operate in 16-
bit, over 65 million shades of gray, resulting in smoother gradations 
and transitions. IJC/OPM internally converts all 8-bit grayscale 
files to 16-bit during printing to take advantage of the 16-bit 
profiles and rendering algorithms (16-bit files remain 16-bit)....

Peter.