I recently bought UV filtering films from a supplier for the fluorescent lamps I have in the lab.

I did a test measuring the UV levels without the film and it was around 45 microwatts per square centimeter (50 cm of distance from the light). With the film, the level is 30 microwatts per square centimeter.

I am pretty surprised. I would expect a very different reading as the film is supposed to cut the 97% of the emission. I use an UVA/B meter form Sper Scientific (mod. 850009). I can’t check the calibration, but I used it last time a few months ago and the readings were in line with the ones of a much more expensive museum UV reader.

 

Thanks,

Emanuele