This chiaroscuro memo seems to "ruin" the drawing which would otherwise be perfect: the hatching is hasty, and the lines are clumsily heavy and thick.

But we must understand that the painter never intended that this sketch would be visible once the work was completed.

In reality, it is this apparently random sketch that permitted his step-by-step progression to the completed work.

Indeed, if the two images, the IR image and the visible image, are overlapped, we see that the shaded parts of the Saint's modeled features correspond exactly to the hatching, in its position, and in its varying intensity. Once again, the IR image shows how an underdrawing imposes techniques and methodology through its very unique use.

Cecilia Frosinini, OPD, Firenze.