Haze

Haze is a thin, uniform aerosol intended to be invisible in itself. Its only job is to give the air something to scatter light off, so that beams read as beams. Without it a moving-light rig in a clean room is a set of pools on the floor and nothing in between.

It is not fog and it is not smoke. Fog is a visible cloud, produced by vaporising a glycol fluid, and is meant to be seen. Smoke is the product of combustion. The three are routinely used as synonyms by people who then get surprised by the result.

The fluid base matters. Glycol-based haze is the common choice. Oil-based haze is atomised rather than heated, produces finer particles that hang longer and read better in beams, and is held to a stricter airborne exposure limit — and the two are not interchangeable in a machine.

The real planning issue is detection. An optical smoke detector cannot tell haze from combustion products and will alarm. Haze has to be raised at the site survey, in writing, so the venue can arrange zone isolation through its own fire-alarm contractor, notify the fire marshal where that is required, and post a fire watch — a person standing in for the disabled detection. A venue with building-wide rather than zoned detection often cannot accommodate it at all. Finding that out on show day is finding out too late.

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

• Moving head A fixture that pans, tilts and changes colour, beam and pattern on command — bought in three distinct flavours that are routinely confused when a rig is specified.
• Followspot A manually operated spotlight that keeps a pool of light on somebody who is moving — still the only reliable way to do it, and a position that has to be built into the rig rather than added later.
• Stage wash The even, flattering light a person stands in to be seen — the least glamorous part of a lighting plot and the first thing a camera exposes as missing.