Stained Glass

 

Origin and Significance of Stained Glass

Stained glass has ancient roots, but it became especially prominent during the medieval period, particularly in Christian church architecture.

The earliest known examples of coloured glass date back to ancient Egypt and Rome used decoratively in windows and mosaics. In the 12th–15th century, stained glass became a hallmark of Gothic cathedrals in Europe, reaching its peak in France, England, and Germany.

•    Biblical Storytelling: In a largely illiterate society, stained glass windows illustrated scenes from the Bible saints’ lives, and moral lessons, serving as a visual scripture for the masses.

•    Spiritual Atmosphere: The interplay of light and colour symbolized divine presence, aiming to elevate the worshipper's spirit and represent heavenly light entering sacred space. Stained glass contributed to the aesthetic grandeur of cathedrals like Chartres and Notre Dame.  It influenced architectural design, as Gothic architecture with pointed arches and ribbed vaults allowed for taller structures and larger window spaces.

How colours are added to stained glass

1. The colours in stained glass are created through a combination of chemistry and high-heat techniques, primarily by adding metallic oxides to molten glass (silica + flux + stabilizers) during its manufacture.

   | **Color**      | **Metallic Oxide/Additive**     |

   | -------------- | ------------------------------- |

   | Red (ruby)     | Gold chloride or copper oxide   |

   | Blue           | Cobalt oxide                    |

   | Green          | Iron oxide or chromium oxide    |

   | Yellow         | Silver compounds (silver stain) |

   | Purple         | Manganese dioxide               |

   | Brown/Amber    | Sulfur with iron or carbon      |

   | White (opaque) | Tin oxide or bone ash           |

2. Silver Stain Technique for Yellow Tones): Introduced in the 14th century, silver compounds (like silver nitrate) were painted onto clear glass and then fired. The silver migrated into the glass surface, creating a range of yellows from pale lemon to deep gold.

3. Flashing: In some cases, a thin layer of coloured glass is fused to a clear base (called “flashed” glass). Artists can etch or abrade parts of this layer to create detail or shading effects.

4. Painting and Firing: Artists also use glass paint (made from ground glass and iron oxide) to add details or shading. This paint is fired in a kiln so it becomes permanent.