I am very surprised that nobody has comments on sepia toners. I thought this place was plenty of people doing true darkroom activity.
Another doubtful paragraph on Fomatoner fact sheet says that the original image must have deep shadows, as the toned image will be lighter. This is at least surprising, as sepia toning is a notorious mild reinforcing technique, and the classic texts usually report it also as a reinforcing treatment for thin negatives. Does anyone have comments on this?