Audience scanning is when a laser beam is projected at the audience instead of over their heads. The laser beams actually reach out and touch the audience, covering them in rippling sheets, waves and tunnels of emerald and colored laser light. Audience scanning is the most crowd pleasing laser effect for any kind of laser show and one that completely immerses the audience in the laser experience.
Audience scanning though is not with out its dangers and strict controls are needed to ensure the safety of the audience. Audience scanning is considered to be too risky in the US and subject to constantly changing regulations, is banned in most if not all states. Unlike the US, Audience scanning is allowed in Europe subject to controls outlined by the International Laser Display Association (ILDA) after 1998.
The main control for audience scanning is Maximum Permissible Exposure (MPE). MPE is the maximum exposure a member of an audience been scanned can have to a laser light that is considered safe. If a venue does not exceed the MPE, audience scanning is safe and permissible. MPE is standard in all countries but the methods used to calculate the amount of light an eye is subject to varies and is calculated more conservatively in some countries than others.
Despite the concerns some people have, audience scanning in a venue that uses MPE to control the laser show is extremely safe. MPE’s have been calculated to include a safety factor and are set 10 times below the level of exposure that would cause an injury in 50% of people’s eyes. This means that people would need 10 times more exposure to laser beams before they had a 50% injury to their eyes.
After the recent debacle in Russia where a number of people at a rave where blinded by audience scanning, many clubbers are afraid of audience scanning. The Russian rave tragedy occurred because the organizers and people operating the lasers had no idea what they were doing, were not trained and were not professional. One of the golden rules for audience scanning outlined by ILDA is pulsed lasers that deliver short high energy pulses of light are NEVER allowed. Those cretins at the Russian rave used pulsed lasers.
If you are at a rave that uses audience scanning and are uncertain of the safety, speak to the people operating the lasers and ask them about MPE. If they give you an intelligent answer then you can relax and enjoy the night. If they have no idea what MPE is, leave the venue and contact local authorities before some one gets hurt.