Only value, no detail
The first stage begins with a light gestural sketch that establishes the proportions and the angle of the head. Once the placement is confirmed, the broad masses of light and shadow are blocked in with the side of the pencil, keeping every edge soft and every mark subordinate to the larger shape.
Even at this early point the form reads as three-dimensional: the illusion of volume is carried entirely by the relationship between the lights and the darks, which is precisely why the value structure must be resolved before a single detail is drawn.
The stone comes back
With the value structure settled, the final stage sharpens the drawing detail by detail: the brow ridge and the bridge of the nose are re-measured against the centre line, the deep-set eyes are placed on a level axis, and the carved curls and braided beard are built up in short, directional strokes that follow the turning of the stone.
Proportion is checked constantly at this point — eye line at the half-height of the head, the ear aligned between brow and nose base, the beard occupying roughly the lower third. A discrepancy of even a millimetre in these placements will read as a wrong face, no matter how carefully the surface is rendered. The darkest accents, in the eye sockets, under the lip and inside the fractured edges, are saved for last, and the highlights are lifted back out with a kneaded eraser.