How does stained glass get colored? learn from an expert!


Detail of 13th Century Stained Glass in Chartres

Most everyday glass is clear but stained glass windows in churches and homes are beautifully colored. How does stained glass get its wonderful colors? Find out from a stained glass expert.

Etched glass at Govinda's Restauran... x
Etched glass at Govinda's Restaurant, Tucson

Glass is made by fusing silica sand mixed with alkalis such as potash or soda, and lime. The color is produced either by adding a metallic oxide to the raw materials or by staining the surface with special paints.

The term “stained” glass is really a misnomer. Most so-called stained glass in church and residential windows is colored glass produced by adding metal compounds to the glass formula. A second, and important, category of colored glass is produced by paint or stain applied to the surface (and often fired onto the glass in a kiln). Jump to this section to learn about painting on glass.

Glass colored by the addition of metallic compounds

Metals giving colors to glass
Examples of colored glass

Most “stained” glass is really just clear glass that has been colored by the addition of metallic compounds or elements. Colored glass comes in two main varieties – Cathedral (transparent) glass or opalescence (opaque) glass. Jump to this section for a list of metallic elements and their corresponding glass colors.

Glass colored by staining with “silver stain” or paint

The origin of the term “stained” come from the silver stain that was developed in Medieval times to decorate stained glass panels in churches. It was mainly used to paint faces, hands and feet of figures – detailed that cannot be easily represented by lead lines.

German, Nuremberg; Panel; Glass-Stained 1525 - after Sebald Beham

Painted stained glass is produced by applying “stains” or paints to the surface and firing the painted glass in a furnace or kiln. Follow this link to learn more about silver stain.

Laminated glass (colored by a vinyl interlayer)

A less important category of colored glass is made by sandwiching a colored vinyl interlay between two sheets of clear glass. This type of product has the benefit of being available in large sheets suitable for architectural applications.

Laminated glass
Laminated glass is made by sandwiching vinyl between two sheets of clear glass. The resulting panel is a form of safety glass – the vinyl holding the glass together in the event of breakage.
Colored Laminated glass
By using a colored vinyl interlayer colored glass is created

Follow this link to learn about tinted architectural glass.

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The history of stained glass

Glass had been known since Egyptian times but it was not until the so-called “father of chemistry”, the Shi’ite scholar Jabir ibn Hayyan (known as Geber) in the 9th century that the technique of coloring glass was first understood. Geber discovered that the addition of metal oxides could change the tint and hue of glass and he recorded dozens of formulae.

The knowledge of glass coloration reached its early pinnacle in the work of medieval stained glass artists and craftsmen building the monumental gothic cathedrals of Europe.

Stained glass in the Gothic cathedrals

Cathédrale de Chartres - Chevet - Vitrail de Charlemagne
Stained Glass window (Life of Charlemagne) – (follow this link for attribution)

Astonishing use of color in this 13th-century masterpiece of stained glass from Chartres Cathedral. Note the extensive use of cobalt blue and the bright red lites (made with the addition of gold).

John La Farge and Louis Comfort Tiffany

The 19th century saw revolutionary artists like John La Farge and Louis Comfort Tiffany create works with opalescent stained glass. Tiffany despaired of purchasing glass from Europe and so hired his own expert from England (Arthur J. Nash) to manufacture glass for him in the USA.

Louis Comfort Tiffany stained glass

Sunset landscape with wisterias by Louis Comfort Tiffany represents the use of custom-made opalescent glass to represent the colors and textures of nature. Sunset, distant hills and shimmering water are realistically rendered using opalescent glass and a technique of multilayering called “plating”.

Modern (20th century) stained glass

The 20th century saw the birth of modernism in stained glass with major artists like Henri Matisse, Georges Braque, and Fernand Léger designing windows in abstract styles but still taking full advantage of the vibrancy and brilliance of color.

photo of stained glass window at the United Nations building in NY by Marc Chagall

Peace window by Marc Chagall

Installed in the UN building in New York in 1964, the Peace window was dedicated to the memory of Dag Hammarskjöld. Characterized by cobalt blue glass, it features references to Beethoven’s 9th Symphony.


So what exactly causes the colors in colored glass?

Various types of metal compounds and elements are responsible for the vibrant colors of stained glass. Note particularly that you will pay a premium for red glass because it contains gold.

Common compounds and their associated colors are:-

  • Deep blue or violet: Cobalt oxide
  • Light blue or green: Copper compounds
  • Purple: Manganese oxide, nickel
  • Yellow: Cadmium sulfide
  • Ruby red: Gold chloride
  • Reds: Selenium compounds
  • White: Antimony oxides
  • Yellow/amber: Sulfur
  • Fluorescent yellow-green: Uranium oxides
  • Emerald green: Chromic oxide
  • Greens and browns: Iron oxides
  • Amber/brown: Sulfur compounds
  • Ambers & browns: Carbon oxides
  • Deep amber & amethyst: Manganese oxides
  • White: Tin compounds
  • Black: Manganese + cobalt + iron
Emission spectrum of a metal halide lamp

Emission peaks in a metal halide lamp show how colors are associated with specific electromagnetic wavelengths. Metal ions in the lattice of the glass absorb certain wavelengths of light, varying depending on the metal, leading to the appearance of color.


Emotional & spiritual symbolism of color

The wonder of color allowed representations of biblical stories to be presented to peasants not only as a kind of poor man’s bible allowing believers who could not read Latin to learn the stories of the gospels but also as man’s message to the creator, in praise of the Lord, illuminating their cathedrals with multicolor lights as if from heaven itself. Glass colors developed a vocabulary of symbolism in Christianity that is summarized here:


Why not experience the beauty of colored stained glass?

Stained glass is a wonderful hobby

Get started with this collection of all the tools & supplies needed to set up your own home studio. Quality tools, lead, stained glass, and solder.


Silver stain on glass

The term “stained” comes from the use, in the early 1300s, of silver stain. Silver compounds (notably silver nitrate) are mixed with binding substances (like gamboge gum), applied to the surface of glass, and then fired in a kiln. They can produce a range of colors from orange-red to yellow. Used on blue glass they produce greens. The way the glass is heated and cooled can significantly affect the colors produced by these compounds

The method of silver staining has remained the same since the 14th century. The pigment is combined with ingredients such as gamboge clay and turpentine to help the mixture lay smoothly on the glass. Heating the glass and stain in a kiln creates a chemical reaction causing an ionic exchange between the glass and the silver to produce a range of yellows on the surface of the glass. These can range from pale lemon to dark orange. Unlike paint, which when heated becomes fused to the glass surface, the yellow stain actually becomes a part of the glass

German, Nuremberg; Panel; Glass-Stained 1525 - after Sebald Beham

Ecce Homo panel circa 1525

Glass painted with vitreous paint and silver stain (after Sebald Beham), Nuremberg, One of a pair from the Metropolitan Museum of Art.


Painting on glass

Combined with silver staining, glass paints were applied starting in the middle ages to define the details of eyes and facial features. The artists used vitreous paints – that is paint composed of finely ground glass particles mixed in a fluid to produce bold opaque lines (sometimes called grisaille painting) that were fired in the kiln to fix them permanently to the glass. In subsequent years a wide range of glass colors and enamels has been developed to extend the palette of the glass artist.


Stained glass needs light

Look at any church windows as you drive down the street and you will notice that the stained glass looks dull, gray, and uninspired. This is because colored glass needs, above all things bight light to bring it to life.

Stained glass and sunlight

To stand in front of a stained glass window illuminated in bright sunlight is a magical experience. In the video below, gold imparts a bright red color to the glass – a color that is projected as a spectacular slide show on the white tiled floor.

Looking more closely, you can see the way the handmade water-glass distorts the light, giving a natural organic quality with ripples trapped forever in the heart of the glass – ripples that were frozen in as the hot liquid cooled.

Prairie-style leaded stained glass by Artistry in Glass, Oro Valley residence Tucson, AZ

Stained glass and lamplight

Other classic examples of the way stained glass comes to life when illuminated are the amazing leaded glass lampshades invented by Louis Comfort Tiffany:-

Tiffany Pond Lily Lamp

According to Christie’s – “A rare and important ‘Pond Lily’ table lamp, circa 1903. Leaded glass, patinated bronze. 26½ in (67.3 cm) high, 18 in (45.7 cm) diameter of shade.” Sold for $3,372,500 on 13 December 2018 at Christie’s in New York.

Tiffany adapted the copper-foil method to create masterpieces of glass art in the early 20th century.


Significance of colors in Christianity

Red: is the color of blood and represents the blood of Christ or the martyrdom of saints. It can also indicate strong emotions such as love or hate.

Blue: (the color of the sky) indicates heaven, the Holy Spirit, hope, and truth. Lighter shades of blue are sometimes used to represent the Virgin Mary.

Green: (the color of trees and grass) is optimism, growth & renaissance being the color of nature.

Violet: is passion, suffering, agony, truth & love.

White: depicts purity, holiness, virtuousness, chastity, and innocence (often associated with Jesus/God).

Black: black symbolizes suffering and death in the Bible but in windows, it is only seen as outlines (grisaille) defining figures in religious stained glass.

Yellow: represents the joy and presence of God. It is also used for the haloes of saints, or the Gates of Heaven and to symbolize divinity, power, and glory.

Gold: represents God’s holiness, majesty & divinity.

Brown: means renunciation of worldly possessions and a symbol of existential angst and death.

Purple: was the color of kings, and important people so is used to depict royalty or God the Father.

Faux stained glass

We have concentrated here on traditional stained or colored glass that is assembled into windows with metal came or copper foil. There are substitutes for the real thing that appeal to the frugal shopper but not to the purist. Consider these options available on Amazon if you would like to save money:

Excellent modern stained glass paints that can be fired in a domestic oven at 325 degrees F
Liquid lead is a thick paint that simulates real lead came and enables the production of imitation stained glass. (not recommended for the purist)

Which should you choose for your home – etched or stained glass?

The bottom line is that colored glass costs much more than etched glass. So if you are on a budget, etched glass is generally the better choice. Check this post for full details.


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John

I was an exploration geologist and University Professor working in Botswana, Zambia, Brazil, Saudi Arabia, the Netherlands, and other countries before opening Artistry in Glass in 1986. In my more than 30 years of experience, I have brought my technical abilities as a scientist to the trade of glasswork. In this time I have become an industry expert in glass and glass-related skills. Watch out for special insider tips developed from my detailed knowledge of the glass business.

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