Now that the shadows and dark tones are roughed in, you can begin developing the form by adding halftones.
It is best to add tone in blocks or ‘planes’ as you still want to keep things as simple as possible to allow for changes.
As each plane turns towards the light it will get darker – the closer the tone is to the shadow, the darker it will be.
It will enhance the sense of the big form of the head by figuring out where the lightest highlights are and darkening away from this point generally and gradually.
Once the planes are blocked in, you can go back and erase highlights and lighten tones where necessary.
