Uncovering Leonardo da Vinci's Secrets in Codex Atlanticus Folio 843

Researchers at Politecnico di Milano conducted an in-depth study on folio 843 of the Codex Atlanticus, a collection of Leonardo da Vinci's drawings and writings, to understand the origins of black stains that appeared on the modern passepartout that binds Leonardo's original folios. The study revealed the presence of starch glue, vinyl glue, and inorganic nano-particles made up of mercury and sulfur, which had accumulated within the cavities formed between the cellulose fibers of the passepartout paper. The particles were identified as metacinnabar, a mercury sulfide in an unusual black crystalline phase, and were likely formed due to the addition of an anti-vegetative salt in the glue mixture used in Grottaferrata's restoration techniques and air pollution.