Mural painting executed on an intonaco already carbonized, but not yet completely dry, using colours mixed and diluted with water and lime. Considered for a long time as inferior to fresco, fresco secco was amply practiced between the 16th and 19th Centuries in response to the necessity to accelerate the working time of continually more ample surfaces. Compromising with this need, a development in the method for preparing the intonaco is emphasized in this arch of time. The intonaco becomes thicker (to slow the drying) and rougher (to allow the colours to firm better). Given the variants that one observes in the technique of mural painting, in many cases, it is difficult to stabilize an exact caesura between the techniques of mezzo fresco and secco painting.