Art Chowder July | August, Issue 22 | Page 38

Manufacture of basic lead carbonate by the “stack” or Old Dutch process, showing corroded white lead. photo courtesy Natural Pigments, Inc. F or centuries white lead was made by a fairly simple corrosion process. Metallic lead was suspended in earthenware vessels over vinegar. A large number of these were stacked one above another, upon a bed of manure, in a chamber that was closed up for a period of time: the so-called “stack” (also “Dutch”) process. After a series of chemical reactions took place, the stack was taken down and the white pigment was collected. White lead production by the Old Dutch process ceased in the 20th century. White lead artists’ oil colors are still available, typically under the name Flake White, but the pigment made the old way had some interesting qualities the modern method does not. Old Dutch white lead contains particles of different sizes and shapes and this affects how the paint flows under the brush. 38 ART CHOWDER MAGAZINE