Transmissive properties of Medieval and Renaissance stained glass in European churches

Abstract

Medieval stained glass is often described by how its clarity contributes to the lightness or darkness of a sacred interior. Using high dynamic range (HDR) imagery (a low-budget, time-efficient means of photographic data collection) to estimate luminances (or per-pixel brightnesses), the relative transmissivities of adjacent panels of glass are obtained for the first time in a variety of medieval churches in western Europe. In order to carry out a comparison between different interiors, red glass was assumed to have a fixed average transmissivity, based on data that suggest that the glazing transmission of red panes is relatively constant. This red standard was then applied over a large database of images collected from different churches to provide a quantitative index of stained glass light transmission. The results indicate that the use of brighter colours during the 12th century admitted more light compared to 13th-century glass. Furthermore, the more translucent glasses of the 15th and 16th centuries appear to have increased light transmission into the interior by as much as an order of magnitude. The resulting change in indoor illumination significantly altered the human visual perception of the sacred interior as glazing preferences evolved over the course of the late Middle Ages.

Stained Glass and Climate Change: How are they Connected?

“…Instead of the bright, higher translucency glass (whites, yellows and light blues) that dominated many Romanesque glazed windows, Gothic apertures were often largely filled with richly coloured glass that restricted interior lighting (Grodecki, 1983). The relative transmissivity differences between windows from different eras has been recently studied in Simmons and Mysak (2010) and quantitatively confirms Grodecki's observations on the increasing colour saturation of stained glass in the first half of the thirteenth century. Therefore, the substantial expansion of window coverage at the beginning of the Gothic era may have been associated with a notable decrease in glazing transmission, which would have limited the lighting gains associated with the birth of Gothic architecture.…”

“…The anomalously bright patch on the vaults near Tours' Cathedral choir is associated with window 105, a band window which has modern replacement glass in its upper levels (Grodecki et al, 1981). More modern glass is present in the clerestory of St-Ouen than in the other two examples, but many of the windows have transmissions comparable to the original glass (see Simmons and Mysak, 2010). The contrast in lighting between different forms appears to be less significant in Tours under cloudy conditions and Le Mans under sunny conditions, which produces a more even illumination of the architecture.…”

The Grande Rose of the Reims Cathedral: an eight-century perspective on the colour management of medieval stained glass

“…The absorbing properties of medieval stained glasses also determine light transmission inside Gothic monuments and influence human visual perception. Brighter colours during the 12 th century and more translucent glasses of the 15 th and 16 th centuries both admitted more light compared to 13 th -century glasses 14 . A recent modelling suggests that the change to translucent glasses could be a response to climate change.…”

The representation of skin colour in medieval stained glasses: The role of manganese

“…Stained glass windows play a central role in the medieval Gothic architecture and are invaluable witnesses of the evolution of the building technologies of this time (Rehren and Freestone, 2015). In addition to be an iconographic support, these translucent glass windows were bringing light and colour in the buildings Mysak, 2010 and. On figurative panels, character heads are one of the most important glass pieces.…”