The Ansel Adams examples are interesting because AA very deliberately manipulated the relative intensity of tones in his photographs. In fact, I'm not sure how

The Ansel Adams examples are interesting because AA very deliberately manipulated the relative intensity of tones in his photographs. In fact, I'm not sure how applicable the current training method (desaturate a color photo, colorize it, compare it to the original) is to actual B&W photographs. Black-and-white photography is not a simple matter of desaturation.