Can Halogen Lighting Change the Color of Glass?

By Les Hansen
September 2003 - Issue #365

We received this question from a member recently. Here is Les Hansen's answer. Les has done a lot of research on the chemistry of glass.

Halogen lamps (light bulbs) are incandescent, but they create more ultraviolet radiation than standard incandescent light bulbs and also operate at much hotter temperatures. Fluorescent bulbs, on the other hand, operate at much cooler temperatures. Ultraviolet radiation is what causes glass to become "sun-purple" in color, either by long-term exposure to sunlight or by short-term exposure to lamps that heavily transmit ultraviolet radiation. So, theoretically, halogen lamps might have a slight potential to impart color to glass. However, halogen lamps are used today by many museums, so the likelihood of them imparting harmful levels of ultraviolet radiation to materials on display must be very remote.

The major cautionary notices regarding halogen lighting revolve around their very hot operating temperatures and, consequently, the tremendous heat that they generate. This could be a concern for display areas that are not well vented. Some convention centers place restrictions on the use of halogen lamps for displays in exhibition halls because they are regarded as a fire hazard.