Sorry I didn't respond earlier, but I've been out of town. Recently the Carolina Area Registrars (CAR) met in Greensboro at the Weatherspoon Art Gallery. Nora Kuper hosted the meeting and presented a program on their experiences with the installation of UV protection on windows in their lobbies. Mark Shumate, a consultant with Clear Defense Film Technology, also made a presentation. He noted that no film is 100% effective. Even if a window faces north, UV rays bounce off other objects and can harm works of art (& artifacts). The life expectancy is 25-30 years, then you can add another layer. There is no damage to historic glass. However, I was bothered about applying this film to original glass in historic buildings. I have since found out that a historic house here in Raleigh decided to install UV shades. The bottom of the shade is held down by a metal bar painted to match the color of the window sill. The effect is hardly noticeable. for further information, contact Nora Kuper @ (910) 334-5770; Mark Shumate @ (910) 275-0970; or Sarah LeCount, Mordecai Historic Park, Raleigh, (919) 834-7314. Good luck! Martha Battle Jackson, Registrar (919) 733-7862 NC Historic Sites Fax: (919) 733-9515 109 East Jones Street [log in to unmask] Raleigh, NC 27601-2807 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Opinions expressed in this message may not represent the policy of my agency. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Don't part with your illusions. When they are gone, you may still exist, but you have ceased to live."--Mark Twain ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~