Pastel drawing on botanical bas-relief/ Soothing Art

Pastel drawing on botanical bas-relief/ Soothing Art - POTTERY CLAY. The pottery clay can be different colors. Here, in Finland, I usually buy it in our local art and craft shop. - PLASTER (GYPSUM POWDER) mixed with WATER in 1:1 PLASTER PRIMOSUPRA 70 made in Germany 1:1 ratio is 1 part or 1 unit of a particular quantity. For example 1 cup of cold water and 1 cup of gypsum powder. To find out the amount of water, you need to multiply the width by the height. For example, this round shape with a diameter of 25 cm. 25cm X 25cm makes 625. So for this particular job, you will need 625g of water.