Poppe Totte kindly gave me the permission to publish his one hour quick sketch demo, where he shows his approach, thought process, and rendering method. For this demo he used a Conte 1710 charcoal pencil, and fairly smooth drawing paper (not smooth newsprint). Here follow his drawing and accompanying commentary
Step 3, go really dark on the darks, refine edges and shapes, also almost 15 mins which is really not that fast, but again, I went for accurateness.
I also didn’t start on the hair since it gets really easy to smear the whole drawing. Notice though that I sort of already have it in shapes and planes.
Step 3.5. Thiis is where the magic happens, smear out the darks and build up the halftone. Go lighter on the light parts but dont leave any white spots. This stage is only 2-3 minutes.
Last step, final rendering, I refine some of the halftones, going lighter and darker where needed. I use a cut hard eraser for the highlights. Fingers or a stump where needed. Approx time 15-20 mins.