15th-Century Paint Recipes Discovered

Most art enthusiasts look at a Renaissance masterpiece and enjoy the painting’s aesthetics. But John K. Delaney, a conservation scientist at the National Gallery of Art, studies artworks’ binders, the material that suspends the pigments and makes up the paint’s bulk. Delaney’s team reports a noninvasive way of mapping the chemical identity of a painting’s binders via an absorption spectroscopy technique common in remote sensing called near-infrared reflectance imaging spectroscopy (Analyst 2013, DOI: 10.1039/c3an00926b). The team showed that a painting made in 1475 by Cosimo Tura used paints that were composed of egg yolk binders, animal skin glue binders, and mixtures of these binders and other ingredients. They showed that the near-IR spectroscopy technique accurately identified the painting’s binders by comparing their results with results obtained previously via conventional, and destructive, sampling and analysis methods.