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A scrim or gauze is a very light textile made from cotton, or sometimes flax. Its light weight and translucence means it is often used for making curtains. The fabric can also be used for bookbinding and upholstery.

Scrims have also seen extensive use in theatre. The variety used for special effects is properly called sharktooth scrim. However, in theater a scrim can refer to any such thin screen, and are made out of a wide variety of materials. The advantage of scrims is that when lit from the front they can appear opaque to the audience, until a change in stage lighting (lighting from behind) makes them almost fully transparent. When lighting behind a scrim to make objects "appear" behind it, the scrim itself should not be lit, as it will detract from the translucency. Lighting to make the scrim appear opaque should be done at an oblique angle to the scrim. The general rule is anything lit behind the scrim (even lights that originate from the front) will be seen by the audience. Scrim has a rectangular weave that is similar in size in its openings to a window screen.

Another type of scrim is called bobbinet / bobbinette, this material has a hexagonal hole shape and comes in a variety of hole sizes. It is used for a number of lighting effects in the film and theatre industries.

Scrim can also be used in theatre in combination with a cyclorama or backdrop. The idea is similar to the other uses. When the drop is lit (or images or video are rear-projected onto the back of the drop), the images or colours projected are visible. However when the drop is not lit, the images or colours will disappear. A scrim can also help dull the image, creating a greater sense of depth.

Another effect is caused by layering two scrims, or even by placing a mirror behind a scrim and lighting it: the familiar moire effect. This can often cause audience disorientation.

Scrim is also used in clothing, usually covering the face or head. This allows the wearer to see out, while preventing others from seeing in. This may also be combined with camouflage to completely hide a person, such as a sniper.