Lambert recommended colors in a wax-based medium for the construction of his pyramid. This may have been an effort to overcome the problems of body color experienced by Waller, Lichtenberg, and others.
Source: Johann Henrich Lambert, Beschreibung einer. . . Farbenpyramid. . . (Berlin, 1772).
Credit: Photograph © 2002 Board of Trustees, National Gallery of Art, Washington, D.C.