Richard Knoppow wrote: > Traffic film is used in those cameras which record > people going through stop lights, etc. It is IR sensitive so > that invisible IR flash can be used. This is partly so that > violators are not tipped off but mostly to avoid distracting > other drivers with powerful flashguns going off. In NYC the red light cameras have a very visible flash of light when they go off. They are set up to only trigger when they sense a vehicle in the intersection while the light is red. I've always assumed that the visible flash was sort of a "Aha! We got you!" notice to the drivers in the intersection. I'm not even sure that the flash is for photographic purposes (i.e., I think that the camera itself may be IR based like everyone else uses). -- Brian Reynolds | "It's just like flying a spaceship. reynolds@xxxxxxxxx | You push some buttons and see http://www.panix.com/~reynolds/ | what happens." -- Zapp Brannigan NAR# 54438 | ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.