Moisture Static - blue flashes
Posted 26 May 2005 - 11:53 AM
Posted 26 May 2005 - 03:25 PM
I'm a post supervisor shooting super 35 mm - 4 perf - in NYC and when the film is tranfered we're seeing blue flashes of light that someone at Technicolor describes as moisture static. Has anyone experienced this or knows the cause?
If the unprocessed film picks up excess moisture (very humid conditions or condensation on a cold roll), the film emulsion gets a bit "sticky" with the added moisture. When two film surfaces are slightly "stuck" together and pulled apart when unwinding the roll, you can generate static that will cause a blue glow at the point of separation.
You can see this effect for yourself. Go into a totally dark room and let your eyes accomodate to the darkness for a few minutes. If you pull the tape off a film can, or perhaps take the protective paper off the sticky side of a "Band Aid" bandage, you will likely see a bit of static discharge as the sticky surfaces separate.
The solution to the problem is to control the moisture content of the film. In really damp conditions, a bit of dessicant (silca gel or molecular sieves) can help keep the opened film roll dry. Always let a can of film warm to ambient temperature before opening, or condensation may form on the film surface if its temperature is below the dew point.