Oil pastels
Oil pastels are often known as a wax oil crayon. Unlike
pastel pencils, however, this is a wet medium that is created using
oil and a wax binder. The surface of an oil pastel window is therefore
less powdery, but more difficult to set with a fixative.
Oil pastels are considered a fast medium because they can be carried
around easily in drive form. However, many serious paintings are made
from oil pastels. There are some problems with durability though because
when the oil doesn't dry it continues to permeate the paper and degrades
both the paper and the color layer.
There are many types of oil pastels. Generally, they fall into the
category of scholastic, student or professional. The more skilled one
becomes, the more it makes sense to move toward professional quality
pastels.