Historic paint analysis

Historic paint analysis is the scientific analysis of architectural finishes, including not only paints but also metallic finishes and clear and translucent finishes used on historic buildings. The primary purpose of such analysis is to determine the color of the finish used at a particular time in the building's history, usually the original construction, but not always. Secondary purposes include determination of ingredients such as media (water, oil, latex, etc.) and pigments (organic pigments, inorganic pigments, dyes, etc.). Paint analysis is also used at times as a dating technique for various building elements.

Typical problems encountered in historic paint analysis include such things as paint loss, surface deterioration, newer materials, substrates, delamination, media and pigment deterioration, and alligatoring.

Historic architectural paint analysis finds its roots in the early twentieth century in the United States. The historic preservation movement began in 1849 with the preservation of Mount Vernon, the home of George Washington. Early preservationists began to realize that paints and finishes which had survived were very important but may not have been the original, or historic, finishes. Interest in historic wallpapers also developed with the interest in historic paint and color. One of the earliest endeavors came with the restoration of Williamsburg, Virginia funded by John D. Rockefeller in the 1920s. Early investigations by simple scraping of the finishes by Susan Nash of the surviving original buildings yielded a palette that became popularly known as Williamsburg colors.

In the 1950s and 1960s serious efforts at investigating original paint colors were underway at Independence National Historical Park in Philadelphia by architect Penelope Hartshorne Batcheler. Her pioneering efforts introduced, for the first time in this country, the use of a stereo microscope to more closely examine the 18th century paints at Independence Hall. Batcheler also introduced the use of the Munsell Color System for matching and referencing original paint colors. Her landmark publication, "Paint Color Research and Restoration", was the very first publication concerning the analysis of historic architectural paints for determination of original colors. At the same time, in the United Kingdom, microscopy of paint samples was developed by Joyce Plesters of the National Gallery, London who worked mainly with easel paintings but also with samples from wall-paintings.

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