Year: 2025
Type: article
Abstract: Leaded oil medium, historically used by artists to modify paint properties, was prepared by treating oil with litharge (α-PbO), massicot (β-PbO), or minium/red lead (Pb 3 O 4 ), forming lead soaps. Alongside lead soaps, recent synchrotron-based structural micro-probe analyses revealed presence of lead formate (Pb(HCOO) 2 ) , lead formate hydroxide (Pb(HCOO)(OH)), shannonite (Pb₂OCO₃), plumbonacrite (Pb 5 (CO 3 ) 3 O(OH) 2 ) and neo-formed hydrocerussite (Pb 3 (CO 3 ) 2 (OH) 2 ). This study reviews their occurrence in historical and model systems and explores their early formation and distribution in leaded oil model systems. Model systems were analyzed using optical microscopy, GC-MS, ATR-FTIR, µ-FTIR, and SR-µ-XRPD. This study shows that, beyond lead soaps, various lead-based compounds form heterogeneously in leaded oil systems. Lead formate crystallizes and migrates within the first days of curing, while lead formate hydroxide and lead carbonates (shannonite, plumbonacrite and neo-formed hydrocerussite) tend to concentrate in the globule areas. This paper proposes potential chemical formation pathways for these unusual lead-based products in leaded oil systems.
Source: npj Heritage Science
Language: English
Subfield: Archeology
Field: Arts and Humanities
Domain: Social Sciences
Open Access status: hybrid
OpenAlex ID: W4413851532