“Linen Scrim is still a finer and closer weave than bobbinet and is used mainly for effects such as an apparition or a vision scene, i.e., a subject is painted on the front of the scrim. When the light is removed from the front and brought up to reveal an object behind the scrim, the painting on the front disappears. Since scrim is only seventy-two inches wide, there are seams when it is used to form drops. These seams must be sewn as finely as possible so they will not show.”
Bradford Ashworth’s “Notes on Scene Painting” (1952, page 3)
The images below are from the Pasadena, California, Scottish Rite Theatre for the 15th degree Treasure Chamber scene.