No doubt when doing craft work is so important to master certain skills as fully acquainted with the characteristics and possibilities of each of the materials being used.
A regular in many tasks relating to crafts and decoration is the bitumen, it is nothing more than petroleum-based dye that is diluted in turpentine or tremetina which are most often used to give an artificial aging wooden surfaces ceramic cake or gypsum, but is also used to color just different pieces of porous base.
The bitumen is used because in addition to its effect of veiling is a product that once dry you can polish base of rubbing with a cloth, allowing for play of light and brightness in the treated parts. This bitumen also admits to being decorated with acrylic paints or other water-based, but must know also that the components that constitute the bitumen requires significant drying time which is determined on the packaging of purchase.