Limewash was the early predecessor to modern paint products. But in its true application and effect on a wall it really acts more like an absorptive stain and it has different characteristics than modern paints. Limewash is not a coating that lays on the surface of the wall, but rather it penetrates into the surface of brick, stone and wood to create a peel-free surface. After it hardens limewash remains vapor permeable and will not trap moisture in the wall.
One of the attractive things about this traditional material is that it gradually wears off the surface of the wall and leaves a very pleasant uneven aged look. Many architects and designers seek this look but they have had challenges creating it for their clients because they have been using the wrong products, such as paint, to achieve the effect.