Harder than lead

Exploration Stage: Bonmarito Villa
From: Professor
Description: Adeline is eccentric. But there's a lot of good stuff in that curly head of hers. For example, the idea of restoring van Eyck's formula. He is known to have experimented with "lead salt"...look for it.
Completed: It seems that Di Fiori used "lead salts" similar to those used in living paintings. It hardens the paint faster. Don't try this at home!