Sanguine Glass Paint, C3

Process & Production

The ingredients called for were iron rust (Fe2O3·nH2O), sodium chloride (NaCl), and sulphur (S), mixed together in the proportion of 2:2:1 by wt. Wine vinegar (CH3COOH) was to be added until a paste was formed. The mixture was made according to the recipe, and then fired in an electric furnace for eight days at 600°C (red fire). It was surmised that adding vinegar created an acid environment to facilitate the oxidation reaction of rust impurities such as magnetite (Fe3O4) toobtain haematite (Fe2O3). Then the powder was grinded and painted on glass with gum Arabic dissolved in vinegar.

Find more at:
Â. Santos, M. Vilarigues (2019). Sanguine Paint: Production, Characterization, and Adhesion to the Glass Substrate. Studies in Conservation 64, 4, 221-239.

Recipe Details

Ingredients:
iron rust (Fe2O3·nH2O), sodium chloride (NaCl), sulphur (S), vinegar (CH3COOH), gum Arabic. Recipe Source: Sanguine reconstruction of a recipe number 58 by Montpellier (“Recette per fare vetri colorati et smalti d’ogni sorte havute in Murano”, 1536) in Luigi Zecchin’s “Vetro e Vetrai di Murano” (1987, 247–76).