T he term “Stained Glass” in the modern sense means something very different than it originally did hundreds of years ago. During the principal period of large-scale catheral construction in Europe, windows were colored by way of additions of chemical “stains” and/or enamels onto the individual surface of each pane of glass in a window. The panes (pieces) were fired in a kiln prior to assembly in order to develop and set the colors onto the surface permanently. The glass in these ancient cathedral windows was essentially clear before the staining and enameling.
“Stained Glass” as we now know it refers to windows that are made of glass that is colored within the glass itself. The chemical formulas to made basic glass colors has been known for many centuries. The glass produced using these traditional chemical ingredients was lagrely translucent or semi-transparent. Artistically, it was limiting and could be boring. The two pioneers credited with resurecting the dormant interest in stained glass in the late 1800’s, John La Farge and Louis Comfort Tiffany, experimented exhaustingly to discover not just new colors, but new exciting varieties of glass.
Both of these energetic leaders were, not surprisingly, accomplished painters and colorists. From the early 1870’s, the enthusiasm of these men to (independently) advance, and elevate, the art form of stained glass brought startling results. Literally thousands of new colors were created in varying degrees of translucency. As time went on rich hues developed that had earlier been considered impossible in the medium of glass. It was natural for other companies to begin competing to create unique glass, and soon America gained a fervor for imaginative stained glass windows.
Different colors of glass were blended together on the marving table to make steaked or striated glass. Various textures--ripples, mottles, granites, glue-chips, hammers and so on--evolved to give dimension to what began as a flat medium. Probably the most important innovation was the discovery of “opalescent” glass, which affected the translucency of glass to varying degrees, but tended to bring a rich “fiery” glow to windows that contained it. Opalescent glass is an American invention, and it distinguishes the windows made in America.