Normally, black and white printing, when done with profiles, for instance using Quad Tone RIP, will at best, not show in Photoshop the tint or deviation from neutral of the actual print. This is problematic because prints are not perfectly neutral even when no tint is selected. Additionally, subtle tints can provide an artistic touch to black and white prints. Tools for making ICC profiles, such as those from X-Rite and the open source Argyll require data sets that contain a range of RGB values and corresponding Lab (more formally L*a*b*) values result from measuring the printed colors.
ABWProfileMaker provides a process for creating ICC compliant profiles for use in Photoshop and other programs that use ICC profiles to accurately display (aka softproof) and print black and white images using black and white printing modes.
Black and White (and gray) modes are available on most printers designed to reproduce high quality prints. Examples are Epson's "Advanced Black and White" mode and Canon's Black and White Photo Print modes which are selectable in the driver.
https://github.com/doug3236/ABWProfilePatchesAdded an Argyll profile I created that shows softproofing one of Keith's B&W images. It's from the 9800 with Matte and PK ink so really high L* min. It has identical performance to the I1Profiler created ABW profile except that the Argyll profile's Perceptual is identical to Rel. Col. (Argyll's default) whereas the I1Profiler profile has a separate table for Perc. and looks a bit different.
Updated the GitHub repo with improved structure, readme and examples including statistics. Windows command line executable included.