Scrim

A scrim is a loosely woven fabric, usually sharkstooth, that behaves differently depending on where the light is. Lit from the front with nothing lit behind it, the weave fills in and it reads as a solid surface. Bring up light on what is behind it and take the front light away, and it becomes transparent.

That transition is a reveal that requires no moving parts, no track and no cue other than a lighting one. A band appearing behind a logo, a stage dressing itself mid-sentence, a product emerging from an apparently solid wall — all the same trick.

Two conditions make or break it. The front light has to be kept off the scrim from a steep angle or from the sides, because any light spilling on to it from the front during the reveal keeps it opaque. And nothing behind it may be lit until the moment of the reveal, which means masking the back space and keeping work lights off it.

A scrim also takes projection and front-lit content reasonably well, and is often hung in front of a cyclorama or a set for exactly that reason.

It is worth saying what a scrim is not: it is not a cheap projection surface and it is not a substitute for a drape. It is a lighting effect that happens to be made of fabric.

Event lighting — owned inventory, our own crew, and a site survey before anything is specified.

• Cyclorama (cyc) A large, smooth, pale cloth lit as a coloured sky behind everything else — the simplest way to give a stage depth, and unforgiving of creases.
• Backdrop The surface behind the stage — fabric, printed, hard scenic or an LED wall — and the decision that sets what the lighting and the cameras can do.
• Masking The drape that defines what the audience cannot see — legs at the sides, a border across the top, and the difference between a finished stage and a visible crew.