4 DRIERS: SUMMARY

The only lead compound, and indeed the only metallic drier, that was offered in 19th-century artists' colormen's catalogs as a separate product, until the last decades of the 19th century, was lead acetate. It was also the most frequently mentioned drier in the artists' instruction books and handbooks. It is only through descriptions of the preparation of drying oils that we learn of the use of litharge, white lead, and red lead. Except in a passing reference to decorative painting, litharge was not suggested as an addition to paint, and other lead compounds, such as red lead and white lead, were not generally recommended as driers per se but did receive occasional mention as additions to slow-drying pigments to enhance their drying properties (see table 3).

Other materials, such as zinc and manganese, would have been added during the commercial preparation of drying oils. Zinc was used throughout the period under study as a drier in its own right, and manganese, apart from its presence in certain pigments used as driers, was introduced into artists' materials as a specific compound only late in the century, primarily as a replacement for lead.

Considering the number of avenues by which driers may have entered an artists' paint or medium, during the processing of the raw materials, in the commercial preparation of the paint and media, and by the artists themselves, it would be expected that at least some of the paint film defects in paintings from this period are associated with the excessive use of driers.