What’s In a Name?
Historic Water-Based Paint Terminology
Historic finishes are often poorly documented and the types of painted finishes are often inaccurate. It is important to use the right terminology as this can help with dating, recording regional uses, and identifying the hierarchy of usage in a building.
A widely-used historic finish was water-based paint. This category of paint was inexpensive, easy to use, far less toxic than oil-based paint, and often viewed as sanitary due to alkalinity.
We outline the basic components for each type of water-based paint below, but it should be noted that each type of water-based paint could have various additives, such as alum, which helped harden the coating.
Distemper: this generic term used to cover almost all forms of water-based paints in the United States. Distemper paint is a water-based paint formed with calcium carbonate, usually whiting or chalk, bound with glue and mixed with water and, if wanted, colored pigments. The English continued to use the term “distemper” for whiting-and-glue-based paints while the term “Kalsomine” or its variations were used for whiting-and-glue paints in the United States by the mid-nineteenth century (Kalsomine discussed further below). The United States began to refer to almost all calcium carbonate and calcium sulphate hemihydrate paints as distempers.
The earliest water-based paints used in the United States were limewash and whitewash. These terms are used almost interchangeably now, but they are different.
Limewash: is made with slaked lime putty thinned with water and often colored with mineral-based pigments. The pigments need to be alkali resistant.
Whitewash: is made with less caustic and less alkaline whiting, along with a number of other ingredients depending on the painter, the substrate, and environmental conditions. It often had size or glue added to the whiting, although occasionally it was made with whiting and water.
Kalsomine: Kalsomine paint is whiting, white glue and water. Alkali stable pigments could also be added. Kaolin or white clay could also be found mixed in the binder. By the late 1920’s, Kalsomine was not as extensively used as it was replaced by the more washable Casein and cold water paints. Kalsomine can also be referred to as Calcimine, Calsomine, or Calsamine.
Figure 1: Kalsomine paints
Alabastine: this paint was made with plaster of Paris and animal glue ground together. Plaster of Paris is partially dehydrated gypsum and therefore is not fully calcined, although it is often referred to as calcined gypsum. While Alabastine has similarities to Kalsomine, the whiting is replaced by the plaster of Paris, or calcium sulphate hemihydrate.
Casein Paint (Kasein): Casein, a milk protein, was found to be more durable than hide glue and replaced the hide glue in Kalsomine paints. It could be made using whiting and lime. Once lime replaced whiting completely, it became known as casein paint.
Figure 2: Lowe Brothers Kasein Coating Washable Water Paint