A Glossary of Stained Glass Terms

Abrasion A method of scratching to remove a layer of colour from the surface of flashed glass to create more than one colour with one piece of glass.  Glossay-Abrasion
Annealing Controlled cooling of the glass during the production process or during the firing of paint, in order to remove stresses within the glass and reduce the risk of breaks.  Glossay-Annealing
Back painting Paint applied to the back of the glass to add greater depth to the image.
Badger brush A glass painting brush made from badger hair that is used to smooth out or add texture to a wash of paint. 
Bullseye A thick knob of glass created in the centre of a crown glass sheet where the iron was attached.  Glossay-SG-Bullseye
Cartoon A full size drawing of the design for a stained glass window.  Glossay-17th-cent-swiss-cartoon
Cold paint Paint that is applied to the glass surface but does not need to be fired, this is usually acrylic or oil based paint.
Corrosion The deterioration of the glass. This can be caused by a variety of factors and usually results in pitting, crusting or iridescence on the surface of the glass.  Glossay-Corrosion
Crown glass A method of producing sheets of glass by spinning molten glass attached to an iron. The sheet is thickest in the centre where the iron was attached and is characterized by curved lines as a result of the spinning motion.  Glossay-Crown
Cylinder glass A technique for producing sheets of glass by blowing molten glass into a cylinder (or muff), cutting off the ends then along the top in order to flatten it out into a sheet.  Glossay-Cylinder
Diaper A decorative pattern applied using glass paint to enhance the glass surface.  Glossay-Diapering
Enamel Metallic oxides are added to ground glass to create colour when painted and kiln-fired onto the surface of glass.  Glossay-Enamel
Etch A technique for removing a layer of colour from the surface of flash glass using hydrofluoric acid in order to create two colours with one piece of glass.
Flashed Glass Two layers of colour in one sheet of glass created when making cylinder glass by adding a second layer of molton colour before blowing the glass into a cylinder. The process of glass blowing spreads the second colour into a thin layer which can be etched or abraded to remove areas of colour.  Glossay-FlashedGlass
Float Glass Flat, transparent glass made by floating molten glass on molten tin.
Gems A medieval technique used to create two colours on one piece of glass by cutting a coloured piece of glass, often to the shape of a gem, then using glass paint to fire it to the surface of the glass.  Glossay-Gems
Glass paint Finely ground glass mixed with flux and metal (usually iron or copper oxide) to create shades of black or brown. The powder is mixed with liquid, applied to the glass and fired in a kiln to make it permanent. Glossay-BlackEnamelGlossay-Black-enamel-fragment 
Glaziers Mark A small mark, often a letter or number, either painted or scratched onto the surface of the glass to sort the pieces of glass when removed from the kiln, or to order the stained glass panels.  Glossay-GlazierMark
Grisaille Monochrome painting, for example: Silver stain or black enamel on clear/white glass  Glossay-Grisaille
Grozing Iron A metal tool with a hooked end used for grozing the edges of the glass.
Grozing A technique for shaping the glass using a grozing iron which leaves a distinctive champhered edge.
Insertion Insertions were made by grinding a hole through one piece of glass and inserting another piece of glass inside it using a lead.  Glossay-Insersions
Pot metal This refers to the method in which the glass is given colour by the addition of metal to the pot of molten glass before it is made into a sheet.  Glossay-PotMetalGlossay-pot-metalExample
Cames or calmes Long strips of H shaped lead which are cut to size and wrapped around pieces of glass to join them together to form a stained panel. Each join where the lead meets is soldered to secure it in position.
Kiln Used to fire glass paint which has to be heated to about 650˚C in order for it to permanently adher to the glass surface.  Glossay-Kiln
Lead Lead is the metal that is cast or milled into cames used to assemble stained glass windows. This is because it is flexible for shaping to fit around individual pieces of glass, but also very strong, to provide support and to withstand different weather conditions.  Glossay-Lead
Light The vertical division of a window.
Matt A wash of paint across the surface of a piece of glass.  Glossay-Matt
Muff A mouth blown cylinder of glass which is then cut and flattened to make a sheet of glass.  Glossay-Cylinder
Over painting Historically used as a layer of glass paint or cold paint on top of the original paint layer. This was often used to disguise paint loss.
Pitting Cavities or pits in the glass surface as a result of deterioration/ corrosion.  Glossay-Corrosion
Plating A method used to protect old glass by fitting very thin float glass to the back, and occasionally the front surfaces.
Seedy Glass
Silver Stain    Glossay-SilverStain
Stained Glass This is a slightly deceptive term that is commonly used to describe painted glass held within lead cames. Early medieval stained glass consisted of coloured pot metal glass which was painted and leaded together. Therefore ‘painted and leaded’ glass may be a more accurate definition. The term ‘stained glass’ originates from a technique developed in the 14th century, of applying silver stain to make clear glass yellow.
Stippling/Stipple shading  
Stickwork Paint can be applied to the glass using various methods such as brush and stippling, but then it can be removed using a stick or blunt tool (stickwork) to create to create fine highlights and details.  
Support bars Bars used to provide support to the leaded panels by attaching the lead to the bars with wires.  Glossay-SupportBar
Trace line  
Tracing brush/rigger  
Trefoil A three lobed shape  Glossay-Trefoil
Vidimus Before the cartoon was drawn, preliminary sketches would be made to show what the finished windows would look like so the design could be approved. The approved design was the Vidimus.  

3 thoughts on “A Glossary of Stained Glass Terms

  1. this was so helpful! I was wondering what manner of scratched mark I was examining was on a piece of medieval glass I recently acquired. Now I know!

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