Abstract
The Grande Rose of Reims Cathedral (France), a UNESCO Cultural Heritage Monument from the 13th century, underwent several restoration works during the 20th century. Its colours result from centuries of colour management from which little information remain. We used non-destructive and portable optical absorption spectroscopy to quantify glass colour and determine the colouring species on a large-scale study of this monumental window. We found six distinct colour groups, each containing both medieval and modern glasses, with colouring processes specific to each colour. This illustrates medieval glassmakers’ mastering of glass colouring and modern glassmakers’ management to reproduce medieval glasses colours. Full UV-visible-NIR energy range is necessary for determining the contribution of colouring elements as Fe2+ and Cu2+. Systematic thickness measurements reveal an average glass thickness of 3 mm and demonstrate the major control of chromophore concentration on glass colour. Yellow, red and purple colours arise from a single chromophore each, suggesting the use of well-defined glassmaking techniques leading to robust colour reproducibility. By contrast, blue and green glasses show different chromophore combinations depending on production time, which suggests more diversity in glassmaking techniques.
Highlights
Stained glasses are one of the most impressive features of the medieval gothic architecture
Optical absorption spectroscopy (OAS) allows a non-invasive identification of the chromophores responsible for glass colouring and portable methods have been developed to analyse the glasses without dismantling the panels[11,13]
One peculiar feature of the Grande Rose of Reims cathedral is the use of the green colour in background of trefoils that form the outermost ring of the pattern, while backgrounds were commonly blue and red at this time[19,20]
Summary
Stained glasses are one of the most impressive features of the medieval gothic architecture. One peculiar feature of the Grande Rose of Reims cathedral is the use of the green colour in background of trefoils that form the outermost ring of the pattern, while backgrounds were commonly blue and red at this time[19,20] This peculiar use of green colour on the outermost ring may be motivated by forming a transition between the stained glasses and the outer stone ring, decorated with vegetal sculptures which were probably originally painted. Investigating the various chromophores used for glassmaking provides us with a unique overview of this major artwork and the techniques of glass colour production and use from Middle Age to modern era.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call