The ancient art of making stained glass has remained largely unchanged for centuries. Our tools may have developed and improved but much else remains the same. Understanding how a window is made will give you a greater appreciation and insight into the craft.

The design of the window is the first great task and perhaps the most challenging for the artist. The commissioning process is a collaborative one between the artist, the client and perhaps a small committee from the church. Together a theme is established and this forms the basis for the design work. Time is spent building up a profile of the job requirements and visits are made to the site to assess the location of the window, and the available light.

Church commissions must be approved by the parish council and then the Diocesan Advisory Committee before work can begin.

Nicola Kantorowicz


Full scale cutlines and working cartoons are first drawn. These drawings contain all the information needed to make the window. The cutline indicates the intricate web of lead lines which form the structure of the window. The cutline is used as a template for cutting the glass shapes. I work with the finest mouth blown glass which is made in England, France and Germany. Each sheet of glass is unique in colour and texture and is carefully selected to bring the design to life. The cut glass is mounted onto a glass easel set against the window in my studio so that at all times I am working with daylight behind the glass.


Once the glass is cut it can then be treated in several ways to create pattern and texture to modify the light which passes through it. These processes are PAINTING, ACID ETCHING and SANDBLASTING.



Glass paint can be applied to the glass to create tone, texture and pattern. I apply a matt of paint over the glass surface and then remove some of the paint with different tools and materials to create a variety of marks and to modify the amount of light coming through the glass. The glass can be fired and then more paint applied to build up layers of tone and texture. Soft and stiff brushes, sticks, combs, scrunched up paper or tin foil - a variety of things can be used to make marks on the painted surface.

When the painting is complete the pieces are fired in a kiln at approx.650ºc. This fuses the paint to the glass surface and makes it permanent. The glass pieces are then refixed to the easels to view.

Other techniques can still be applied.


Acid Etching

Hand blown antique glass and flashed glasses are a combination of a layer of clear glass and a film of colour. By using acid or sandblasting the layer of coloured glass can be removed to reveal the clear glass beneath it. By controlling the amount of colour that is removed different textures and shades of colour can be created on the glass.

Various types of stencil or resist can be used to create textures. When working with acid I enjoy mixing the clear sharp cut achieved with scalpel and plastic resists and the softer effects which can be achieved by using print makers resists. These can be scraped and broken down in a much more abstract and textural way.



Some antique glasses have a very thick layer of colour on a clear base. These pieces need to be sandblasted to break down the coloured surface. The abrasive action of sandblasting is often quicker than acid for these pieces. The finished surface is also slightly different from acid work and the glass can have a wonderfully sparkly surface. I also enjoy mixing sandblast and acid work to create different subtle textures.

Each sheet of flashed or antique glass is unique and therefore sometimes unpredictable. I do not know how the pieces will react to the treatment of acid or blasting. This adds an exciting dimension to the work. The skill lies in knowing when to stop each process and how to mix the processes. Results cannot always be predicted or copied again, but each piece will always be a unique original piece of art work.


Nicola Kantorowicz

Once the decorative processes are finished the panels are ready for glazing, soldering and cementing. The cutline is placed on the studio bench and used as a guide for placing the glass pieces together with the lead cames. Different sizes of lead can be used in a panel, some for decorative effect and some for structural support. Once the panel is glazed all the lead joints are soldered on both sides. The panel is then ready to be cemented. This process makes the panel weatherproof. The window is now ready to be installed.