Hello Laura, Bill and Ed are right, I don´t know any standard, and usually yellow filters are enough. The only thing I can add to their answers is that there are comercial fluorescent tubes with a yellow filter inside, in fact a plastic coat around the normal tube, this kind of tubes perhaps are easier to handle. Regards Eowin --- Den ons 2008-10-15 skrev Laura Oropeza Ramos: Från: Laura Oropeza Ramos Ämne: [mems-talk] light type and intensity for a clean room lithography area Till: MEMS-talk@memsnet.org Datum: onsdag 15 oktober 2008 18.29 Hello all, We are planning the construction of a clean room for MEMS polymer fabrication in Mexico City. I can not find information about if there is a standard way to determine the yellow light intensity in the lithography clean room areas. If somebody could give me an advice on this, it would be highly appreciated. Thanks so much Laura A. Oropeza Ramos, Ph.D.