[scottlamb]

Does that work if it's painted over? Or can you mix colorants in as with (exterior) stucco? (Maybe this is considered a kind of stucco? I just had to look it up: wikipedia says "The basic composition of stucco is lime, water, and sand".)

[bflesch]

Nope, I dont think it works when painted over. Some vendors recommend colors which are very open for diffusion such as chalk colors, but every other "common" color based on acryl/latex/etc basically seals it from the air and destroys it over long term.

For clay I know you can add color pigments to the clay itself, most likely you can do the same with stucco for some limited amount of colors. But painting over it with modern products mostly destroys the diffusion properties.

Many people put plastics or other sealing products on top of a clay or lime-based wall and it's a shame.

[ender341341]

I would assume if you paint it over with a latex based paint at least it would massively affect absorption. For oil based paints I have no idea though.