Encaustic Medium is the encaustic paint without pigment. It is available in cakes and now in convenient and cost-effective pellet form. It is used to extend the colors and to create transparencies.
It is important when extending the colors to use the encaustic medium rather than plain beeswax. There are two reasons for this:
1) It maintains the hardness of the film.
2) Encaustic made only with beeswax will develop a bloom in cold temperature that can only be removed by reheating the paint. The damar helps to prevent this blooming.