plaster powder is mixed with water for 12 to 15 hours prior to the addition of pigment. the plaster is applied in one thick coat with a wooden float, and smoothed with the same. before the plaster sets, a flat, smooth, hard stone is used to compress the plaster, then a plastic trowel used for the final polish. it is mechanically polished using stones or abrasives harder than the plaster, providing a smooth, sometimes shiny, finish. lastly, an olive-oil soap solution is used to seal the plaster