Green verditer

Description

Synthetically prepared green basic copper carbonate (analogue of malachite). Green verditer was an inexpensive green pigment first manufactured in the 16th century (a byproduct of the silver refining process) by pouring copper nitrate on calcium carbonate (whiting), followed by washing and drying. In the 18th and 19th centuries, green verditer was used for distemper housepaints and widely used in wallpapers. It has not been extensively documented in easel paintings, but some sources believe it was used more widely than previously believed. It was not usually recommended for use in oil, as John Smith reported in his 1723 edition of "The Art of Painting in Oyl" that green verditer is a "sandy" color that lacked "good body" (p. 24). He goes on to report that "with all the grinding imaginable" the verditers and smalts "will never be well imbodied [sp] with the oyl" nor do they "lye [sp] intirely [sp] smooth in the Working." (p. 28). Despite this, he lists the pigment as a component for painting colors such as "Sea Green" and "Leaves of Trees". By the early 19th century, green verditer saw large-scale, industrial preparation by precipitation from a solution of copper sulphate, to which potassium carbonate was added.

See Malachite and Basic copper carbonate.

Synonyms and Related Terms

Bremen green; green bice; British verdigris, English verdigris, French green

Microscopic Properties

Green verditer can be readily distinguished from its mineral analogue (malachite, also copper carbonate hydroxide) with the polarizing light microscope. Green verditer presents as pale green rounded particles, often forming clusters of, spherulites (anywhere from 2-10um in diameter). Some spherulites show a dark central spot in PPL. Relief is low to moderate, and in XPL the pigment is birefringent with greenish-blue interference colors. Some particles may show extinction crosses, similar to those observed in natural chalks, but often misshapen. See Eastaugh et. al. for discussion of 'green verditer' vs 'spherical malachite' (p. 593).

Resources and Citations

• Bristow, Ian C. "Interior House-Painting Colours and Technology, 1615-1840." New Haven: Published for the Paul Mellon Centre for Studies in British Art by Yale University Press, 1996.

• Eastaugh, N. et. al. "Pigment Compendium: A Dictionary and Optical Microscopy of Historical Pigments. 2nd ed. Oxford: Butterworth-Heinemann, 2008.

• R. Gettens, and E. West Fitzhugh, "Malachite and Green Verditer", Artists Pigments, Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993.

• Harley, R. D. "Artists’ Pigments c.1600-1835: A Study in English Documentary Sources." 2nd rev. ed. London: Archetype, 2001.

• Smith, John. "The Art of Painting in Oyl." London: 1723 edition.