Let There be Light Let There be Light: Let There be Light: Let There be Light Climatic Considerations Climatic Considerations in Medieval Stained in Medieval Stained Glass Aesthetics Glass Aesthetics Gl Gl A A th ti th ti Chris Simmons Chris Simmons D D Dr. Lawrence Mysak, Dr. Lawrence Mysak, L L M M k k McGill University McGill University International Congress on International Congress on International Congress on International Congress on Medieval Studies Medieval Studies 11 May, 2008 11 May, 2008
Outline Outline Outline Outline Motivation and Hypothesis Motivation and Hypothesis Motivation and Hypothesis Motivation and Hypothesis Basic Concepts in Stained Glass Evolution Basic Concepts in Stained Glass Evolution Methods and Concepts in Architectural Methods and Concepts in Architectural M th d M th d d C d C t i t i A A hit hit t t l l Lighting Analysis Lighting Analysis Results Results Conclusions Conclusions Future Work Future Work
Interior Lighting: Motivation Interior Lighting: Motivation One of the most important elements in gothic design One of the most important elements in gothic design The foundations for the relationship between window sizes The foundations for the relationship between window sizes and prevailing climate (cloudiness) established by Wachs and prevailing climate (cloudiness) established by Wachs ( (1964) (1964) ( ) ) Relationships between stained glass design (coloured v. Relationships between stained glass design (coloured v. white) and climate (cloudiness) has been discussed by white) and climate (cloudiness) has been discussed by ) ) ( ( ) ) y y stained glass art historians such as Charles Sherrill (1927, stained glass art historians such as Charles Sherrill (1927, 1931) 1931) Goal of this research: Goal of this research: to evaluate quantitatively the overall to evaluate quantitatively the overall daylighting performance of cathedrals with original stained daylighting performance of cathedrals with original stained glass from different epochs under cloudy and sunny glass from different epochs under cloudy and sunny conditions to see if the climate relationship to stained conditions to see if the climate relationship to stained glass is viable glass is viable
Medieval Interior Medieval Interior Lighting: Primary Lighting: Primary Lighting: Primary Lighting: Primary Sources Sources Daylighting Daylighting – Window size (related to Window size (related to architectural style) architectural style) hit hit t t l t l ) l t l ) – Glazing transmission Glazing transmission Choir Clerestory of Bourges (top) and Auxerre (bottom) ( ( (strongly controlled by (strongly controlled by g y g y y y type of stained glass) type of stained glass) – Time of day, season, Time of day, season, latitude latitude latitude latitude – Cloudy v. Sunny Cloudy v. Sunny Candlelight (small Candlelight (small g g ( ( contribution) contribution) Open Doors Open Doors
Window Size and Glazing Window Size and Glazing Transmission: England Transmission: England Transmission: England Transmission: England English churches English churches tended to contain tended to contain both large windows both large windows and often a and often a and often a and often a majority of white or majority of white or otherwise high otherwise high otherwise high otherwise high translucency glass, translucency glass, from the early from the early y Thirteenth century Thirteenth century York: Five to the Renaissance to the Renaissance Sisters Gloucester: Great East Window
Window Size and Glazing Window Size and Glazing Transmission: Mediterranean Transmission: Mediterranean Mediterranean churches Mediterranean churches Mediterranean churches Mediterranean churches tended to have either tended to have either small windows or small windows or coloured glazing or both coloured glazing or both coloured glazing or both coloured glazing or both Stained Glass historians Stained Glass historians Ch Charles Sherrill, Charles Sherrill, Ch l l Sh Sh ill ill Meredith Lillich and Meredith Lillich and others have postulated others have postulated that these are due to th t th that these are due to th t th d d t t England’s cloudier England’s cloudier Toledo climate and the climate and the M dit M dit Mediterranean’s sunny Mediterranean’s sunny ’ ’ climate, respectively climate, respectively
European Cloud Climatology European Cloud Climatology March, 1990 March, 1990- - 2003 2003 NAO years NAO years NAO+ years NAO+ years Strong latitudinal Strong latitudinal gradient over gradient over gradient over gradient over France France Long-Term Average Percent of Total Cloud Cover, from Meerkötter et al. (2004)
Northern Continental Glass Northern Continental Glass Full Colour and Mixed Full Colour and Mixed Programs (1100 Programs (1100- -1260) 1260) The Grisaille Revolution (1270 The Grisaille Revolution (1270- - 1350) 1350) Persistence of white glass or Persistence of white glass or Persistence of white glass or Persistence of white glass or translucent glass through the translucent glass through the Renaissance (1600) Renaissance (1600) Le Mans Cologne Troyes
Methodology Methodology Methodology Methodology Season: Summer and Winter Observations Season: Summer and Winter Observations Extech 407026 Illuminance meter used for Extech 407026 Illuminance meter used for illuminance illuminance measurements (lux) measurements (lux) Canon Digital Rebel XTi SLR Camera (ISO 100, f Canon Digital Rebel XTi SLR Camera (ISO 100, f- -stop stop 4.0, Daylight White Balance) used to produce High 4.0, Daylight White Balance) used to produce High 4.0, Daylight White Balance) used to produce High 4.0, Daylight White Balance) used to produce High Dynamic Range (HDR) images and collect Dynamic Range (HDR) images and collect luminance luminance data (candela/m data (candela/m 2 ), processed by Photosphere (Ward) ), processed by Photosphere (Ward) Interchurch comparison of specific church sectors Interchurch comparison of specific church sectors (ambulatory, transept, nave, choir) (ambulatory, transept, nave, choir)
Luminance vs Illuminance Luminance vs Illuminance Luminance vs. Illuminance Luminance vs. Illuminance Illuminance is the luminous Illuminance is the luminous is the luminous is the luminous Luminance is the Luminance is the is the is the Illuminance Illuminance Luminance Luminance flux (visible light from many flux (visible light from many visible light emitted visible light emitted directions/second) received directions/second) received each second in one each second in one over a surface. over a surface. direction from a given direction from a given direction from a given direction from a given related to additive related to additive source area source area contribution of luminance contribution of luminance luminous intensity/area luminous intensity/area (with respect to the (with respect to the (candela/m (candela/m 2 ) ( ( d l / d l / 2 ) reflectivity of the material) reflectivity of the material) Brightness Brightness represents the broad represents the broad ambient lighting received at ambient lighting received at A function of A function of A function of A function of a given point, subject to the a given point, subject to the i i i t i t bj bj t t t t th th reflectance and reflectance and inverse square law inverse square law transmittance of transmittance of material material material material
Daylight Factor Daylight Factor Daylight Factor Daylight Factor Toward ceiling Interior Horizontal Illuminance ________________________ x 100% Exterior Horizontal Illuminance In a location with an unobstructed hemispherical sky view Al Always constant for CIE Standard Al Always constant for CIE Standard t t t f t f CIE St CIE St d d d d Overcast Sky 1 (uniformly overcast sky) Overcast Sky 1 (uniformly overcast sky)
Recommend
More recommend
