How does a scrim behave when lit from the front compared to when lit from behind?

A scrim is a type of stage fabric that has specific light-filtering properties depending on the direction from which it is illuminated. When lit from the front, the scrim appears solid due to the way light interacts with its fibers. The front lighting prevents the viewer from seeing through the fabric, creating an opaque effect that obscures whatever is behind it.

Conversely, when the scrim is lit from behind, the fabric becomes transparent. The light from behind illuminates the scrim, allowing viewers to see through it and revealing any objects or scenes positioned behind the scrim. This dual behavior makes scrims highly effective for creating visual effects and transitions in stage productions, leading to the conclusion that they appear solid when lit from the front and transparent when lit from behind.