Limewash
A cheap, breathable wall paint made from lime and water, white unless tinted with pigment.
Also: whitewash, chuna
Limewash is slaked lime thinned with water. Brushed on a wall, it reacts with the air and slowly turns back into a thin layer of limestone. It is cheap, lets walls breathe and is mildly disinfectant, which is why it has been used on houses, barns and hospitals across the world. It dries to a soft, chalky white. Earth pigments or a little indigo can tint it; the blue houses of Jodhpur and Chefchaouen and the yellow of Hoi An are tinted limewash. It weathers and must be renewed often.