Le Mans Cathedral, full-colored windows
Tours Cathedral, full-colored windows
Cologne Cathedral, grisaille windows
Last week I was in San Francisco attending the annual convention of the American Geophysical Union. Every day was filled with cutting-edge climate science presentations, none of which had anything to do with Arts and Crafts or William Morris---until I came across the work of graduate student Christopher Simmons! Simmons has visited many of the great cathedrals of Europe measuring light transmission through stained glass windows. He has documented how a shift in the color choices used in stained glass windows, the "Grisaille Revolution", paralleled a shift to wetter and cloudier climates in Europe at the end of the 13th century. He hypothesizes that "climate changes operating in tandem with trends in aesthetic tastes likely motivated a permanent shift in architectural daylighting strategy" and with transmissivity data collected using a Extech 407026 illuminance meter and a Canon Digital Rebel XTi SLR camera, Simmons demonstrated how "grisaille" windows let in much more light, especially on cloudy days (see pics above).
As Simmons concludes, with a minimum of scientific jargon, "this has important implications for understanding thresholds between climate and architectural design, an increasingly important concern as we undergo a period of rapid climate change."
Some more examples of grisailles......
Grisailles: A term that applies generally to stained glass windows that are kept predominately white.