The urban watercolor sketching book has a few example drawings where there appears robbed red or pink or sepia colored inks used in addition to black. Also there are some grey brushes used for shadow on occasion.
I’ve been doing a lot of sketching without watercolors added. Mostly it is to increase my ink skills. So since I have a micron pen in sepia I thought I would give it a shot. Experimenting with shading and mixing use of the two hues.