When viewed under UV light, dark patches appeared across the painting’s surface.
What does this tell us?
The image on the left is the painting before treatment, it’s a detail of the Madonna and Two Children. And the detail on the right is the same area examined under ultraviolet illumination.
So different materials on a painting, they all respond differently to ultraviolet illumination. We see some areas are light and some areas look dark. What we’re seeing, we see these sort of dark patchy brush strokes all across the face of the infant St. John: his neck, torso, as well as the torso of Christ child and the hand of the Madonna. What we are looking at is retouching. And the retouching is not fluorescing in the same way that the paint has. It’s much more recent and it doesn’t have the same aging properties as the paint.
What we noticed here that was most disturbing is the fact that this retouching is applied in broad brushstrokes. And the question becomes: what’s hiding underneath that retouching? Is it covering areas of loss? Is it covering areas of original paint that are damaged? Or is it just covering original paint?