Sanguine Glass Paint, E4

Process & Production

To carry out this recipe, Aqua Regis was prepared as prescribed by Neri, which involved adding ammoniac salt (NH4Cl) to nitric acid (HNO3), in the proportion of 1:6 by wt, and heating the mixture in a water bath until the salt was dissolved. More ammoniac salt was added to achieve saturation in the solution. After the suspended salt particles settled to the bottom of the container, the solution was decanted to another glass container. Iron filings were dissolved for three days in a sealed bottle with the Aqua Regis solution. The bottle was shaken once a day and on the last day, the solution was evaporated at ≈200°C for ≈20 h, leaving a residue of sanguine powder.
Finally, the powder was grinded and painted on glass with gum Arabic dissolved in distilled water.

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:
ammoniac salt (NH4Cl), nitric acid (HNO3), iron filings, gum arabic, distilled water.
Recipe Source: Sanguine reconstruction of recipe number 19 by Antonio Neri (“L’Arte Vetraria”, 1612, pp 18).