Whitewash

Whitewash, or calcimine, kalsomine, or calsomine is a type of inexpensive paint made from slaked lime (calcium hydroxide) and chalk (whiting). Other additives have historically included water glass, glue, egg white, Portland cement, salt, soap, milk or flour.

Additional recommended knowledge

Recognize and detect the effects of electrostatic charges on your balance

Weighing the right way

Daily Sensitivity Test

Whitewash cures through a reaction with carbon dioxide in the atmosphere to form calcium carbonate in the form of calcite, a reaction known as carbonatation.

It is usually applied to exteriors (as Tom Sawyer was made to do to a fence in Mark Twain's The Adventures of Tom Sawyer). Occasionally it is colored and used on interiors, such as the hallways of apartment buildings. Whitewash is especially effective on adobe-like materials because it is absorbed easily and the resultant chemical reaction hardens the substrate.

Lime wash is pure slaked lime in water. It produces a unique surface glow due the to refraction of calcite crystals.

In the middle of the 20th century, when family farms with dairy barns were common in the Upper Midwest of the USA, whitewash was a necessary part of routine barn maintenance.