Rag painting or ragging is a form of faux painting

Faux painting

Faux painting or faux finishing are terms used to describe a wide range of decorative painting techniques. The naming comes from the French word faux, meaning false, as these techniques started as a form of replicating materials such as marble and wood with paint, but has subsequently come to...

 using paint thinned out with glaze

Glaze (painting technique)

Glazes can change the chroma, value, hue and texture of a surface. Drying time will depend on the amount and type of paint medium used in the glaze. The medium, base, or vehicle is the mixture to which the dry pigment is added...

and old rags to create a lively texture on walls and other surfaces. Ragging can be done as a negative or positive technique. The former involves rolling glaze over the entire surface, and removing it with clean rags to reveal the underlying paint color in a pleasing textural pattern. The latter is accomplished by applying glaze directly to the wall with a rag, and creates a similar pattern. Ragging is a very adaptable finish that can be used in a variety of areas, creating the illusion of an old world texture, but on a flat surface that can be easily painted over.

Ragging can be done in a variety of patterns, including rag rolling, in which the rags are twisted together and then rolled over a wet glazed surface creating the illusion of fabrics such a velvet or silk. Ragging is also often used as a pattern underneath stenciling.