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Stained glass or coloured glass?

20th February 2013

Stained glass or coloured glass?

Stained Glass is a general term used to mean coloured glass and windows made with lead came or copper foil.  But what is it, what are the correct terms and what do they mean?

Stained Glass is often mis-spelt as stain glass.  It is a term which refers to the process of literally staining or painting glass to use in leaded windows.  'Leaded lights' is the correct term for a window made of pieces of glass joined by lead came.  However, most people refer to it as 'stained glass' as that is how it is more widely understood.

Staining glass in the traditional sense is applying silver nitrate paint (called a stain) to glass and firing it in the kiln.  This emparts the bright yellow or orange colour from the silver stain onto the surface of the glass permanently.  Similarly, painting on glass, which is part of the stained glass window making process, is done using iron oxide, lead and other metal based paint which is fired onto the glass to create trace lines, matting and shading.

Painting on glass should be thought of as a method of creating design by revealing the light - essentially applying and removing paint to let the light through the coloured or clear glass onto which it is fired.  Amazing levels of texture and detail from patterns to fabric and even faces can be created by a skilled painter.

Coloured sheet glass is a different matter.  This is coloured all the way through the glass and is often referred to as a 'pot glass' as it is coloured in the pot (the bowl inside a glass furnace).  This is done by adding colour to the molten glass before it is made into sheet form.  Antique glass can sometimes be called 'mouthblown' as it is blown by hand into cylinders and then flattened. Our range of Tatra Glass is an excellent selection of hand blown sheet glass.  It has a wonderful light bubbly effect (known as seeds) which catch the light.  Hand blown glass is unique and there can be some variation between sheets.  We also stock St. Just blown glass from France and some Lamberts Glass from Germany.

Antique is different to crown glass, which is spun into a large round disc (called a rondel) then cut to remove the lumpy pontil mark in the centre called the Bullion or Bullseye. This was the cheaper piece and often found in pubs and general domestic glazing, the expensive crown glass was the flat areas around the edge that would be cut and often leaded into a window.

Much of the sheet glass that we stock is made by rolling the molten glass through rollers to flatten and/or texture the glass prior to annealing (cooling slowly to remove stress caused by melting).  This is true of glass from Kokomo, Spectrum, Bullseye and our Cathedral Glasses - the name 'Cathedral Glass' generally refers to single coloured rolled and textured glass which is often inexpensive compared to Antique glass.

Streaky or wispy glasses are made with two or more colours to create vibrant swirls in the sheet.  This can be transparent or Opal which refers to a translucent or opaque (opalescent) effect.

Fusing glass is made specifically for melting together in the kiln.  Ranges of fusing glass like Bullseye or System 96 are tested to ensure they are compatible (note: you can not mix glass between ranges, keep your System 96 separate from your Bullseye in the studio!)  It is slightly more expensive as there is additional testing and processes involved to achieve this.

There is so much glass available, please feel free to call us if you need help with your choice, or more information. Or why not book onto a course and learn to make stained glass windows with us!

 

 

Posted by: Creative Glass Guild

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