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York Glaziers Trust is the oldest and largest specialist stained glass conservation studio in Britain. YGT is a charitable trust dedicated to the care and conservation of historic stained glass in York Minster and throughout the UK. Discover more
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- Illustrated Glossary
To help you understand the medium of stained glass better, here is an illustrated Glossary:The raised knob of glass marking the point at which the pontil iron was formerly attached to the centre of a crown of glass. These thickened pieces are usually cut off and discarded, although in the interest of economy they were sometimes used for decorative effect in less expensive secular or domestic settings.From the Latin calamus, meaning a read. Cast strips of lead, H-shaped in section and cut to the requisite length, were used to hold glass pieces together in the assembly of a stained glass panel. The centre of the lead is called the heart, while the overlapping areas that cover the glass edges are called the flange or leaf. From the end of the 16th century onwards calmes were milled rather than cast. Milled lead often reveals the marks of the teeth of the lead mill on the heart which can sometimes be inscribed with names and dates. Leads are soldered at the intersections in order to make the panels rigid and strong.The full-size outline drawing from which a stained glass panels is made. For much of the medieval period the cartoon was drawn out on a whitened table and was not, therefore, preserved at full size. Only in the 17th century were cartoons marked out on paper, meaning that they could more easily be stored and retained for adaptation and reuse.The deterioration of the glass surface, usually the result of chemical decomposition of the base glass brought about by exposure to moisture. The process can manifest itself in pitting or crusting of the surface and will eventually reduce the thickness of the glass and/or result in holes. Any surface decoration is lost as a result.The general term denoting the range of ironwork set into the masonry of a window to provide support for stained glass panels (see also armature,stanchion, lug-bar, T-bar).A coloured glass made by the application of a thin layer of coloured glass to a base glass of another colour (most commonly uncoloured) during the blowing of a sheet. The flashed upper surface can either be ground way (abraded) or removed with acid (acid-etched) to create complex decorative effects. This is most commonly found as red on an uncoloured base (flashed ruby).The flat, grooved metal tool used to cut and shape glass throughout the medieval period. Glass cut with a grozing iron has a distinctive 'nibbled' and chamfered edge.A flat, slotted support bar to which stained glass panels are attached using a wedge of metal.A bar set horizontally into the masonry of the window opening to which stained glass panels are tied with lead or copper ties, preventing panels from flexing out of the vertical plane.An application of thin paint to the glass.The vertical support bar set into the masonry, internally or externally (or both). In some cases the stanchion passes through a lug in the horizontal saddle bar.A method of modelling achieved by dabbing the wet surface of unfired glass paint, usually with the bristles of a dry brush.T-shaped in section, set horizontally into the masonry of a window opening at the divisions between stained glass panels, each bar supporting the weight of the panel above.A strong line of paint, delineating the main lines of a design.(Latin 'we have seen'). A term used to denote the scale-scale approved design for a window, prepared prior to the preparation of a full-size cartoon.
Another chance to see the BBC4 documentary on the Great East Window of York Minster and the work of York Glaziers Trust. Click here