Stained glass

As a material the term generally refers to glass that has been coloured by adding metallic salts during its manufacture. The coloured glass is crafted into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, held together (traditionally) by strips of lead and supported by a rigid frame.

Painted details and yellow stain are often used to enhance the design. The term stained glass is also applied to windows in which all the colours have been painted onto the glass and then annealed in a furnace.

Stained glass, as an art and a craft, requires the artistic skill to conceive the design, and the engineering skills necessary to assemble the decorative piece, traditionally a window, so that it is capable of supporting its own weight and surviving the elements.

Although usually set into windows, the purpose of stained glass is not to allow those within a building to see out or even primarily to admit light but rather to control it. For this reason stained glass windows have been described as 'illuminated wall decorations'.

The design of a window may be non-figurative or figurative. It may incorporate narratives drawn from the Bible, history or literature, or represent saints or patrons. It may have symbolic motifs, in particular armorial. Windows within a building may be thematic, for example: within a church - episodes from the life of Christ; within a parliament building - shields of the constituencies; within a college hall - figures representing the arts and sciences.