The surface of many Old Master paintings has been affected by the appearance of whitish lead-rich deposits, which are often difficult to fully characterise, thereby hindering conservation. Painted in 1663, Rembrandt’s Homer is an incredibly valuable and much-loved painting. Like many Old Masters it has a long and eventful past, which has taken its toll on the painting’s chemistry. The test of time and environmental factors, combined with the painting’s history, caused a barely visible, whitish crust to form on the surface of the painting. This crust indicates that chemical reactions are occurring which could potentially pose as a risk for Homer and other old paintings if not kept in stable museum conditions.