Stained glass: building a picture out of light

Stained glass · 4 September 2026

Stained glass is the only painting that needs light straight through it. The glass is coloured in the melt, cut to a drawing, detailed with paint and fired, and the pieces are held by lead came. Without a window behind, the picture does not work: the colour lives only in transmitted light.

What a window is made of

1. Glass. Colour goes into the melt, so it never fades: gold and copper give red, cobalt gives blue.
2. Cutting to the cartoon. Sheets are cut to a full-size drawing.
3. Painting and firing. Faces, folds and shadows are painted in black and fired so the paint fuses to the glass.
4. Lead. Pieces are joined with came and soldered; the lead matrix becomes part of the drawing.
5. Installation. The panel is fixed into the opening with ironwork that carries weight and wind.

Roundel and panel

A roundel is a small circular disc with a single scene, usually painted on clear glass. These went into ordinary domestic windows, which is why they survive one at a time. A panel is a composition of many coloured pieces made for a church or state window. The archive holds 60 panels and 12 roundels.

What carries value

Original glass with no later insertions, intact painting and a sound lead matrix. Replacements show in colour and thickness; re-leading and "refreshed" painting lower the grade. Provenance matters too: a panel tied to a known building is worth more than an anonymous fragment.

What the archive holds

The collectioner.art collection holds 125 works in coloured glass from 1200 to 1960 across 26 makers and collections – the Metropolitan Museum of Art, the Cleveland Museum of Art and the Smithsonian Institution, all CC0.

Open it: the Stained glass collection. Nearby: tiles and portrait miniatures.