Fig. 8: Perugino, Study of Kneeling Youth.
From: Materiality and techniques revealed in drawings by Raphael, Leonardo da Vinci, and Perugino
Photomicrograph acquired using a 360-degree raking light attachment: Hirox AC-1020S. Original magnification: 90×. The location of this image is indicated by a blue arrow in Fig. 6b. Automated focus stacking software was used to create a 3-dimensional heat map and XY chart in micrometers of the area, showing the variable depth caused by the metalpoint stylus incisions in the preparation layer.
