More often than not, a pastel painting is framed with a mat board and behind glass. This is because pastel paintings are delicate and a simple touch from a hand or affects from a room's enviroment can ruin the painting.
A space of about 1/8" is left between the mat board and the painting, this accomplished two things: It ensures the mat board does not touch the painting and that pastel dust that falls from the painting does not get stuck between the glass and the mat. Often, UV or Museum glass is chosen to protect the painting from fading.
