Every time I get on the web I find another misguided definition of "stained glass". The reality is that like many terms it can actually mean different things in different contexts. Here I aim to discuss stained glass, leadlight and reproduction stained glass in order to give the reader sufficient information to wade through all the "expert" definitions. It can get quite convoluted so this post is deliberately simplistic. The point is every expert usually has an agenda to push and as you read on you'll start to see how this influences how they use specific terms and the definitions they perpetuate.
Stained Glass in its simplest context refers to glass that is stained, i.e. coloured. Glass is generally coloured in it's manufacturing process by adding metal oxides whilst the material is still molten. Ruby & Cranberry pink glass for example requires gold to achieve this colour. Hence it is the most expensive coloured glass. Many people refer to red glass as the most expensive or assume any pink be similarly expensive. In fact a good proportion of reds are now made from copper. Still proportionately more expensive than some other oxides but it's not gold! For more on glass colouring, particularly in it's historical context have a look at this article http://1st-glass.1st-things.com/articles/glasscolouring.html
The other way one might stain glass is to "paint it". Painting glass is really much more literally staining it but painting is an easy metaphor. In short stains or enamels are applied layer by layer and fired between each application. Different stains require different levels of heat to achieve fusion. Stain does not wash of glass like a paint nor scratch or fade the way modern reproduction glass stains or films do. It is actually a process of after market staining if you like. Hence why we are able to restore such glass a thousand or more years down the track. Ecclesiastical (church) windows are the most obvious example. You can have a look at a church window "under construction" here: http://tinyurl.com/m3c6sm Another period example of this type of work is the Victorian roundel. 
While we're on the roundels I'll digress momentary back to the key topic of stained glass in Sydney. This sunflower roundel (pictured above) is prolific throughout domestic residences here in Sydney from the late Victorian era through to the federation period and possibly slightly beyond. The move to Californian bungalows making this style of stained glass design less relevant. To date we have restored, replicated and otherwise worked on several of these little historical gems but continue to be none the wiser regarding the original artist, or possibly as he would have thought of himself, the artisan or craftsman (and given the period I'm gonna guess 'he' & there is certainly another blog on the topic of artist versus artisan). Suffice to say we don't know who filled our city full of sunflowers. So if anyone reading this does please comment.
Back to topic.
Bound up in the definitional issues of stained glass is the term leadlight and further to that reproduction stained glass, glossed over above. Leadlight is really the technique used to hold the panel together. H-section lead cams are cut soldered and then filled with a sealant (the details of which get a bit tedious if your not a hobbyist so we'll save that again). This in it's purest form is "leadlighting". Louis Comfort Tiffany exemplified this in the late 19th and early 20th centuries as his studio began designing in the leadlight itself. Prior to this it was more a means of holding small pieces of glass together but now the paint work was being abandoned as he crafted glass that itself formed the image in conjunction with the lead lines.
Welcome Australiana, nouveau, deco. (pictured left)
Around this time design also came to use clear and clear textured glasses as key features in the design. You'll see many Californian bungalows in Sydney featuring leadlights that are principally designed with clear and clear textured glasses (clear referring to the absence of stain, texture being about literally that) with only small pieces of duck egg blue opaque detail.
Of course the example I've found in our gallery also incorporate some additional violet detail, but look to the tiny squares at the corners of the central detail.
So really there you have. Stained Glass and Leadlight. The only term yet to be clarified is the nature of 'reproduction stained glass'. This is a single sheet of glass that has self adhesive lead stuck to it (on each side) to resemble a traditional panel and is then either flooded with a "stain" that is more like a heavy duty version of the hobby paints you might buy to paint glass ware at home or coloured film is applied. Variation of texture is not possible in this form. This has it's place but I'll leave the applications of traditional versus reproduction to Sean (twitter: @sdingham or become a fan of Renaissance Stained Glass on Facebook). This seems to be widely referred to as "stained glass" in Australia to differentiate from the traditional. Unfortunately this is either tricky marketing or simply misguided as traditional stained glass has most definitely already claimed the name and has been so defined for at least 1000 years.
