>>3262734https://www.onlandscape.co.uk/2011/05/kodaks-new-portra-400-film/>portra 400>~19 stops>B&WOne could probably get 20 stops+ by using N-3 development or or more.
Bruce Barnbaum describes a technique, using HC-110 @ 1+15 for 1 minute, then 1+119 for 10 minutes +/-. This apparently yields very high DR.
page 148-149 in "The Art of Photography"