Definitely critical. UVPS also supplies these for whatever bulb size you have. I am sure that there are other companies out there that sell the same stuff. Joel Provence Engineered Materials Systems -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Adamson, Steve Sent: Tuesday, April 14, 2009 11:23 AM To: KLand@csir.co.za; General MEMS discussion Subject: Re: [mems-talk] Vinyl window films for UV processes I think most yellow filter films will reduce UV from windows. Also do not forget the Fluorescent lights in the room. You will need to filter these as well. Regards, Steven J. Adamson Market Manager, Asymtek