Dear Tom,
What is it about sunshine that makes colors fade?
Eddie Krillenberger, Hinsdale
Dear Eddie,
Sunlight causes the colors in just about everything–cloth, plastic, paint–to fade over time. It’s due to the effects of the infrared component of sunlight, and the chemical process is known as photodegradation.
Patricia Dunwoody of the Technical Association of the Pulp and Paper Industry says chromophores, light-absorbing bodies present in dyes, “… absorb colors in particular wavelengths. The wavelengths which the chromophores do not absorb are reflected back to our eyes, and we see these wavelengths as a particular color.”
“The bombardment of chromophores by ultraviolet light causes the eventual molecular breakdown of the dyes, resulting in the loss of color that we call fading,” she noted.
———-
Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
