Both done with white Gelly Roll pen, white Uni Posca brush pen, and water-brush with dilute Lexington grey ink, A6 – 25 minutes each
A life-cast of William Blake’s head (bought many years ago from the National Portrait Gallery when they were much cheaper and painted black), and a plaster-cast of my right hand. Sketching in white on black paper is a challenge, all the usual tonal decisions are reversed and shadows are created by omission. But it’s fun to slowly build the volume of the object through the steady accumulation of contour lines, like constructing a wire frame model.
(I’ve tried several white gel pens and the Sakura Gelly Roll ones work best for me, with less clogging, a smoother tip and the most opaque ink. Always handy for adding highlights to a quick sketch, and correcting the occasional wayward line…)