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The deep red of the devil is caused by mixing gold into the molten glass. It forms microscopic gold globules that scatter and absorb other wavelengths, leaving only vivid ruby read shining through, to an orange to golden yellow in glass with less gold globules in the batch mixed.It is the most expensive kind of stained glass togay, and back in the 13th century.The irony is with Cathedrals going up with stained glass windows normally coming from prosperous merchants and guilds...at least one appears to have told the Bishop that he was putting his gold into helping make the high-priced devil appear.
Haven't all devils gone astray at some point?
I love this little devil, I see it every Friday when I go to the Met to draw.A minor correction to Cedarford's explanation: I believe it's gold oxide that usually produced medieval ruby glass. How the gold oxide was obtained at the period, I don't know.
Gold oxide is used in enamels. The Romans were the 1st to add precious metal salts to glass - likely by trial and error - and found that white gold salts made brilliant red glass and dark silver salts made deep yellow glass.Of course they didn't know why. Neither did the medievals. Even today the stuff is better than modern dyes used to color glass because the old stuff that used gold and silver seems to glow, the light coming from a depth within the glass.The incredible Michael Faraday discovered the principle of light refraction in colloidal suspensions and postulated small metallic gold and silver particles in glass reflected, refracted and caused only certain wavelengths to emerge. He recreated it in his lab. Further research in the 90's got scientists all hot again because they found the gold and silver coloring glass was one of the 1st products of nanotechnology. The gold and silver particles come out of compound and form nanospheres 10-20nm across for the desired effect, which explains why glassmakers had such rigid methods of proper temperature it had to be at past the melting point and how long it had to be held at melt to get good colors. Any more or less would create nanospheres too large or small for the desired effect.http://188.8.131.52/search?q=cache:-3Un0Q2ewGIJ:www.pfpc.unimelb.edu.au/news/pubs/pdf/bulletin_janjun_2003.pdf+%22stained+glass%22+gold+red+microspheres&hl=en&ct=clnk&cd=3&gl=usAnd the scientists are excited to see other nanomaterials also display certain properties that larger colections of the same material do not. So research continues at a brisk clip.Anyhow, Palladian, I'm happy I don't live in NYC, but I admit there are big chunks of it I wish we could rip out and relocate in my State. The Met, Museum of Natural History, Cloisters, Fraunces Tavern, a few hundred brownstone dwellings of craftsmanship you don't see elsewhere, and so on..Just as long as no New Yorkers had to come with them.
While in high school I worked in a small stained glass factory, mostly making the actual lead windows out of the painted glass. Some of the artists were quite old then, and remarkably talented (and precise, as mistakes are quite expensive). The style for church windows has retained a certain similarity over the centuries. We didn't make any devils, though. Modern churches don't talk about Old Scratch much anymore, much to his glee (although he seemed quite gleeful back then, too).
New Yorkers are like that devil; expensively made, sinister to the naive, but they're the ones you remember seeing, not the umpteenth boring-ass angel!
Wow, thanks for the information, Cedarford. Faraday is a hero of a friend of mine, I guess I should do some reading about his work in this area. I've studied medieval pigments, but have not gotten into the technology of glass production."Just as long as no New Yorkers had to come with them"The good thing is that 99% of the people I see at the Met each week aren't New Yorkers. The bad thing is that they don't really act any better.
Reminded me of a piece Pete McGrain did for Kokomo glass: Keepers. He had an article in Glass Craftsman a few years back explaining how he worked with glass and paints. Unfortunately, it isn't online. I have it stashed somewhere in the basement, so I'll try to find it and see if he says anything interesting.Pete McGrain gallery
Man I love this blog! I was just going to post some little joke that Matt beat me to ages ago. And I end up with a science and culture lesson.Well done and thank you.Trey
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