This article outlines the traditional oil-based house paints and enamels available in the first half of the 20th century and includes a discussion of the natural oils, gums, and resins used in their manufacture. These paints are examined in the context of the Ripolin enamels used by, among others, Pablo Picasso, Francis Picania, and Sidney Nolan. Ropolin is the first house paint to have undergone extensive scientific analysis, which allows comparisons to be made between these analytical findings and the historical literature. The research to date indicates that Ripolin enamels are typical of the traditional high-grade enamels and gloss paints available in the first half of the 20th century in that they comprise drying oils, often with some resin, and are formulated with good-quality pigments.