Plaster of Paris, an important artistic tool for several mediums, can be used for adding detail in under paintings and for creating sculptures, as well as to add molded designs and texture on frames or other surfaces.
Ingredients
The foundation of plaster of Paris is heat-treated gypsum powder. Chemically, gypsum powder is calcium sulfate dihydrate. To use, it is mixed 2 parts plaster to 1 part water.
Function
Plaster of Paris is also known by the name gesso. Gesso is used to create the foundation for many art forms including sculptures, paintings and gilded frames.
Characteristics
The size and volume of plaster of Paris does not change as it dries, because the gypsum powder dries before the water evaporates. This gives the plaster a smooth finish.
Name Origin
While plaster of Paris use predates the founding of the city of Paris, this gypsum compound is commonly referred to today as plaster of Paris. This is because gypsum is found in abundance on Montmartre hill in Paris.
Considerations
The drying time of plaster can be affected by letting the mixture rest for 10 minutes before it is mixed. This will slow down the process, while mixing the gypsum powder with hot water will speed up the drying time.
