I like the grain of Ultramax, but not the color indoors. I've shot it and then converted it digitally to b&w, but I'd be interested to see it done chemically.
You cannot actually do THAT chemically by altering film development. If you want the exact grain of Ultramax, the right way would be to print it (normally developed) on a panchromatic B/W paper.
Color films have different grain from BW films because the final image is constructed from dye clouds instead of silver grains, dye clouds being bigger, softer and less opaque.
But, when you process a color film in BW chemistry, it gives a silver image just like any BW film. The grain will be very different than when processed in color. Of course, you can affect grain by developer selection etc. but that is true to any BW film, too.
In addition, color films processed as BW are usually very dense and thus hard to scan and slow to print.
If you are after a "color neg" look in the terms of grain in general and grain in highlights, choose a chromogenic BW film such as Kodak's BW400CN or Ilford's XP2 Super. They are processed in color process (C-41), yielding a image consisting purely of dye clouds just like color neg films, just that the only dye used is black in color (instead of cyan, magenta or yellow) so you have a BW image.
