Importance in History
Lead white was the most important white pigment used in the painting history. It was known to the Egyptians, Greeks and Romans and commonly used in ointments and plasters. It was first identified in literature as a pigment by Pliny, who mentions it, among other colors, as used by the ancients to paint ships.
The density of lead white and its opacity are very important to painters. The power that is gives of making strokes of light as incisive as strokes of dark is fundamental to the technique of painting.
Composition and Importance in Oil Paint
Lead white oil paint is made by grinding basic lead carbonate (the chemical name for lead white pigment) in Walnut-oil a drying oil. Normal lead carbonate (PbCO3) or other lead carbonate compounds have at times been mistakenly identified as basic lead carbonate, which has the chemical formula 2PbCO3•Pb(OH)2. Basic lead carbonate contains from 25 to 30 percent lead hydroxide, which distinguishes it from normal lead carbonate. It is this element that gives added opacity to lead white. It also gives it the qualities in oil paint often sought after by artists.Lead white also serves the flexibility of oil paint and extending the life of the paint film. Lead white has a preservative effect of the paint film, and this can explain why Rembrandt`s paintings are in so good condition. As we know that Rembrandt use a lot of Lead white and Lead tin yellow in his paintings.
In the AMIEN forum, Dr. Jaap Boon, University of Amsterdam and AMOLF and formerly head of the MolArt Project, offered these important insights into the role of lead white in oil paint film:
“The role of lead white is multiple. It is a bulk drier that means homogenous drying over the paint film. It reacts with free acids that develop by oxidation of the oil. It links the acids groups of C9 diacids even when they are still acylglycerides thus stabilising the early film (proven by NMR work of Michiel Verhoeven in 2006). At a later stage when the biological ester bonds are gone, it further stabilises the diacids to form a network that is hard to break. And furthermore, it provides a filling material and surfaces for oil-derived compounds to dock.” A theory about why painting from the old masters «like Rembrandt and Da Vinci - Renessanse» is s good preserved is the Leadwhite. It is a fact that Leadwhite has a stabiles..