'Black Earths': A Study of Unusual Black and Dark Grey Pigments used by Artists in the Sixteenth Century
Marika Spring, Rachel Grout and Raymond White
Technical Bulletin Volume 24, 2003
A number of black pigments have been identified in 16th-century Italian paintings in the National Gallery. The 'black earths' are a category of black pigments referred to as black chalks and black stone pigments. Coal-type blacks are now considered as common as other carbon blacks at the end of the 15th and beginning of the 16th centuries. Distinctions between such pigments are presented in this article with detailed descriptions of their composition, colour, physical appearance, tinting strength, and use. Where significant, references to historic treatises are included in the discussion of the historical usage of the pigment.
Coal black is described as a warm black, in which sulphur can be detected by EDX analysis. In several of the occurrences discussed it is associated with chalk, attributed to the natural inclusion of chalk with coal. The black pyrolusite is a natural black manganese dioxide. The pigment is understood to dry in oil. The identification of manganese without iron distinguished pyrolusite from brown umber. Pyrolusite was commonly used in the glass and ceramic industries.
Grey pigments include stibnite, bismuth, and galena. Stibnite is a natural ore of antimony (antimony sulphide). In pigment form, it has a dark grey colour and under the microscope has a metallic lustre. Similar under the microscope to stibnite, bismuth is distinguished by its pinkish grey colour. In the infrared, this pigment has a very dark appearance. Another grey pigment is identified as galena, a black lead sulfide that comes in natural or synthetic forms. A tin-rich bronze powder has been described as similar to stibnite and bismuth.
art history, bismuth, black chalk, black pigment, coal black, galena, Italian, paintings, primary source documents, pyrolusite, qualitative analysis, Renaissance, stibnite, tin-rich bronze
To cite this article we suggest using
Spring, M., Grout, R., White, R. '"Black Earths": A Study of Unusual Black and Dark Grey Pigments used by Artists in the Sixteenth Century'. National Gallery Technical Bulletin Vol 24, pp 96–114.
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