Hi Gail, According to The Museum Environment by Garry Thomson, ordinary "tungsten lamps emit too little UV to require a filter." Tungsten-halogen, tungsten- iodine, quartz-halogen and quartz-iodine emit UV in a wavelength less than 300nm. "This is very potent and must be eliminated. Fortunately, ordinary glass, transparent to longer-wavelength UV, completely blocks this extra- short emission." Fluorescent lamps on the other hand must all be filtered for UV. Hope this helps. Sincerely, David Ryan Registrar Colorado Springs Pioneers Museum www.cspm.org ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).