Friday, 18 May 2012

Design Principles for Stained Glass

  1. Designing for Strength
  2. Responsive Colour selection
  3. Beautiful Design Lines
  4. Design Sources
  5. Reworking Designs
  6. Some practicalities
  7. Conclusion

There comes a stage when each of us moves from using patterns developed by others to trying to realise our own vision. This is the time where, in attempting to reproduce an image from our mind or from natural and man-made forms, that we begin to encounter difficulties with the medium of glass and lead or copper foil.

There are a number of principles that should be kept in mind while designing, or at least referred to when the design is reaching its final stages. This article is an attempt to outline a number of the most important points in designing glass panels, especially larger ones. It also includes some practical applications.

Designing for Strength
Principles of Design Practice for Stained Glass, 1

The panel needs to be strong to last for a long time. Glass is a very resilient material; so is lead and solder. It would be a shame to design a panel in long-lasting materials that will not survive for long because of the design and construction. There are some things to remember about creating a strong panel.

The strength of a panel is in its glass

Glass in compression is stronger than steel. It is only when it is in tension that its weakness - or fragility – becomes apparent. So the structural arrangement of the glass needs to be such that each piece of glass supports its neighbours. It also needs to use shapes that are strong.

Avoid the following shapes:

Hour glass shapes – those where the ends are wider/larger than the middle - are very likely to crack at the narrowest part. If the shape – usually a negative or background one – is necessary, break it up into smaller pieces that make sense in the whole design. It is also possible to add details that will break up these shapes, but be careful that the details do not detract from the whole.

Exaggerated, deep inner curves will eventually crack at apex of curve. If unavoidable, you should consider adding design lines where the glass would break anyway, or moving elements closer together so they almost touch to avoid the single deep inner curve.

Thin long and tapering glass pieces are very likely to crack near the point or be covered by the lead or copper foil. Where you need to have such shapes, try drawing the lead or copper foil lines on the design. You can do this on a piece of tracing paper to avoid messing up your original design. This will show you how the finished panel may look. Alternatively, you can divide the long tapering piece of glass into several pieces so that any flexibility of the whole panel does not break the long thin piece. Short thin pieces are not so likely to be broken by any movement of the panel.

Inadvisable design elements

Lines radiating from a single point also provide weak areas because the glass is divided into long thin pieces which are liable to breakage. Break up long thin pieces of glass with suitable lines. This ensures that the length of the glass is in a strong relationship with its narrowness.

Avoid “hinges” - lines that run from edge to edge (vertical, diagonal or horizontal) – as these provide places where the panel can bend. This is why windows made up of rectangular quarries need so much support and even then over time begin to concertina. Even if the lines do not run all the way to the edge, any significantly long line will put pressure on the glass pieces at the ends of the hinges, for example, a series of formal border pieces or narrow central pieces. A hinge will be a weakness in the long term whether it survives the studio processes or not.

However, we all have seen leaded glass windows with single or multiple hinges that survive for many decades, and only as they loose support from firm cement and the ties to the saddle bars break away, does the panel begin to self destruct. It is important to recognise where these hinges are to be able to place reinforcements on the panel. But the real solution for making a panel that will last, it is best practice to avoid designing hinges into the finished work.

Avoid complicated shapes

Don’t over-complicate the cut lines. This makes for difficulty in cutting the pieces. Also the more difficult it is to cut the pieces of glass, the more likely it is to fail by breaking after being installed.

Responsive Colour Selection
Principles of design practice for stained glass, 2

The graphic form of much stained glass means that the medium is largely about line and colour. This requires that you think about both your and the viewer's response to the colour combinations. Respond to your instincts. Use you feelings about colour and their relationships. Try different colour ways. Formal training does help, but experience develops your skills. The individuality of the piece depends on the use of your instincts about the colour. There are some checks you can make while selecting colours.

Think of colour and impact.
Hot colours tend to have more impact, as they give bright points or areas. Impact can also be created by using non-complementary colours together. If a more subtle impression is desired, use tonal variations without great contrasts.

Vary areas of colour and their proportions.
This provides interest to a panel. It avoids a mechanical symmetrical appearance, even if the design is symmetrical

Think about colour balance.
Although the colours may vary it is important that the weights of the colours are balanced so that the focus of the panel is not lost to another part because of the imbalance of the colour with the design.

Get some distance.
When you are in difficulty selecting or arranging the colour, step back and view from a distance. This is one of several techniques to enable you to get a larger or different view. Others include viewing the design through a mirror, viewing through half closed eyes, look at the design from the other end, and viewing the design from acute angles.

Use your instincts.
When something feels wrong, trust your intuition and use other colours. Colour theory is just that -theory. It is through using your reactions that the piece becomes individual.

Seek out the nuances of the glass.
The tones and textures alter the perceived colour and weight considerably.

Simplicity of line.
Keep the design lines simple when your emphasis is on colour, light and texture. This allows those qualities to dominate the panel, rather than the lines.

Coloured drawings
Always make a coloured drawing before choosing the glass as a reference. This is a rendering of your original idea. It provides a reference as you select the colours. It is something that can be altered, of course, but does provide an essential reference point.

Use the same light as the installation location.
Choose glass colours in the kind of light for which the panel is intended. This is essential, as the glass colour is subtly different in daylight, incandescent, and fluorescent lights.

Be bold in your choices of colour.
Glass artists need to be very aware of light and dark, both in terms of colour selection and in terms of density. A very thick dense glass of a dark shade of any colour will create a much more intense darkness than glass that is thinner and less dense.

Represent the light.
In terms of colour, lighter hues go where the sun shines or where the eye is to be drawn. Pastel shades also indicate brightness and light. This also can be achieved by using the pale opalescent glass to indicate where light is falling.

Represent the shadows.
A denser dark glass can be used to indicate where light does not fall, or where very little light can filter through. It can also play the part of negative space. It is also possible to consider double plating areas where more darkness is needed.

Of course, vitreous paints can be used to control the amount of light in very subtle and realistic ways.

Use chiaroscuro.
This word - borrowed from Italian ("light and shade" or "dark") - refers to the modelling of volume by boldly contrasting light and shade. These contrasts between light and dark can be used in several ways. Darkness can indicate depth of field or distance when used in a general landscape. Or, it can be used to bring a foreground out, making other elements more vivid. The key thing to remember in using stained glass is to not be afraid of dark glasses. They can very useful, even if of very odd hues of colour.

Beautiful Design Lines
Principles of design practice for stained glass, 3

Stained glass is a graphic medium where line and colour are very important. Achieving pleasing lines and forms requires practice and use of various approaches and techniques.

The two dimensional world is one of abstract thought. Work and development are the way to creativity – there is no mystical talent. Practice drawing every day – set aside time to do it, if you normally shy away from drawing as an exercise.

Study and learn from what has gone before. Look at the images and objects you admire and analyse what you like about them and why. Also consider what things could have been done differently. Consider how those changes would affect the character of the piece.

Of course, maintaining your creative attention is difficult, so when blocks occur try some or all of these things:
  • Put the work aside for a day or two before taking it out and looking at it again.
  • Alternatively, pin up the design on a wall where you can look at as you pass by. When you see a change to be made, do it immediately and pin it back up

Get a new perspective, e.g.:
  • Turn it upside down. This will enable you to observe differences and spot inconsistencies
  • Look at it in a mirror. You might see people studying still life or live subjects together with their drawing in a hand mirror to get a new perspective that will help spot difficulties.
  • Put the design on the floor and climb a ladder to look at it. This provides distance and changes the angle at which you look at your design.

Remember that design tends toward realism or abstraction. You need to work on both forms, remembering that glass is a graphic medium that tends toward abstraction. Working on both forms develops your flexibility and knowledge. Having a working knowledge of both enables you to have a responsive approach to the client.

Design Sources
Principles of Design Practice for Stained Glass 4

Use the everyday visual experience and make interpretations and adaptations. E.g.,
  • draw lead lines on an illustration to make it suitable for stained glass, using the fewest lines possible
  • Use your photographs of interesting subjects and scenes

These may never become useable designs or cartoons, but will increase your abilities to design from the real world toward the abstract.

Make and keep sketches as personal references. These do not need to be finished drawings, just a reminder of the thing(s) that caught your eye. Many artists always carry around a notebook to record these observations. Even if you only make drawings on paper napkins, make a folder to keep these separate sketches together.

Take photos of shapes and interesting images. These can then be used later to develop images.

Make up composite images by using overlays or collage. This helps develop your compositional abilities.

Work on abstraction in your design practice:
  • Study abstract representations. Dissect – decomposition is a popular word - and analyse how the work is put together.
  • Use geometric design as an introduction to abstract design. This forces your attention to structure, balance and colour.

Once the distribution of the physical and visual weights is understood, this enables the jump to more free forms of abstraction.

Reworking Designs
Principles of design practice for stained glass, 5

Having created the design, you should consider re-working the designs for a variety of reasons. Some of these are:

  • to save time in the later stages of the work. It all too easy in the excitement of creating a new piece to want to get directly on with making, however this often gives construction or design difficulties that have to be solved in the making, leading to compromises. In general far too little time is spent in the design stage. Time spent on the design will be more than saved in the construction and will produce a more satisfactory piece.

  • to ensure the structural stability of the piece. Although reinforcement should be considered from the beginning of the design, this is the time to ensure that the piece will stand up to the use it will receive during its – expected – long life.

  • Make sure the design is still structurally sound. The design should avoid long nearly straight lines with few interruptions, especially those that go from edge to edge in any direction. The lines should interlock rather than have many joins onto long lines.

  • To make sure you have investigated every possibility to answer the challenges of your design.

  • Reworking will enable you to maintain the essence of the design while simplifying lines and easing the labour of the construction of the panel. Often the design contains a number of lines that are not essential to the whole design.

  • As you re-work the design, you can make sure every curve, dip and angle are to your liking and so improve the whole. Redrawing also helps understanding of the design and the placing of lines. It will also help in considering the placement of lead came and the widths to be used.

  • It gives an opportunity to ensure that you can cut all the pieces. This is the time to look at the negative or background pieces to make sure you can cut them as well as the foreground pieces. Usually people are so concentrated on designing the main image that the background becomes too complicated to cut easily.

Make successive tracings with each change, so there is a record, allowing you to step back wards to an earlier version if necessary.

If this re-working stage leads to the realisation of design problems, there are some things that can be tried:

  • Cropping the design can transform it. The focus of the design can be enhanced by removing some of the surrounding “information”. The change of proportions say from landscape to portrait can make significant differences.

  • Enlarging and using only a portion of the original design can be a solution. This is similar to the cropping operation, but has the added advantage of making the pieces larger and easier to cut.

  • Further simplification of background design lines can be considered. This will bring the focus back onto the main part of the image.

  • Changing relative proportions can transform the design, e.g., by enlarging a busy background, it can be made simpler and easier to read the whole panel.

Some practicalities
Principles of Design Practice for Stained Glass 6

The traditional approach to cartoons meant three versions were necessary. One with all the drawing details, one with the cut lines, and one for layout and leading.

If you are doing a leaded or copper foiled panel without details for painting on glass two copies are the maximum required. I make do with one original, as I have no place to keep the glass pieces laid out while cutting and beginning to lead, nor do I make templates for cutting unless absolutely necessary.

The paper you need is one that is stiff enough to avoid changes in shape or wrinkling with changes in humidity. The paper also has to be robust enough to stand up to lots of movement. Cartridge paper from a roll works well, but is often seen as expensive. Brown wrapping paper is usually stiff enough, although thinner than cartridge paper. If your design is narrow enough, you can use lining wallpaper.

Tracing paper is very useful, if you do not have a light box, as you can trace details from one version of a cartoon – whether new or from an old one – into another. However it changes shape when exposed to high humidity. To transfer the cartoon to more stable or more opaque paper, you can use a pounce wheel to transfer through the tracing paper for the final cartoon.

If you have a light box you can use it to make the transfer, or you can stand at a window with the two sheets of paper taped together to trace the design onto the final cartoon paper.

If you need to make pattern pieces you will need a second copy of the cartoon to cut up. Here you need paper or card that lies flat. You may also find it useful to cover the main cartoon with a water proof covering if you are going to do a lot of grinding and fitting over the cartoon. You can do this by oiling your paper (as for stencils) or by sticking clear vinyl over the cartoon.

Transparency sketches

Use matt finish acetate .25 to .12mm thick. This will later be fixed to Perspex for presentation.

You will need rigger brushes in sizes 0, 1, 2, and 4 for doing the lead lines and other areas of graphic delineation. In using these brushes for lead lines, you want to maintain a line that is consistently thick. It is a different feeling from general image making and you may want to try locking your wrist to maintain a greater consistency of pressure.The paint for the lead lines can be a calligraphy ink or a black acrylic paint. The lead lines and all other tracing is applied to the matt side of the acetate.

Once the tracing lines are all completed, start laying the colours on the backside, the smooth side. The brushes to use are bulbous pointed sables in sizes 2, 3, 5 and 6. The application is in a "floated" versus a "stroked" manner of application. Stroking has a tendency to hasten the drying resulting in streaking. You may find this a bit of a trick at first. It is advisable to place colour throughout the design so it has time to set up and dry a bit, as opposed to putting wet against wet.

When the colour has dried, you can emulate matting on the matt side with an ebony pencil. And if you want to take out some lights, that can be accomplished with carefully placed extender. The extender is also used to make the piece transparent and to emulate a variety of textures available in glass from reamy to seedy.

When the colours are dry, mount the sketch on 3mm Perspex to stiffen the presentation, provide weight and give the presentation with some "substance”. You can also add double matt board doors hinged with smooth electrical tape to keep the lacquer colours away from sustained sun. Also when open, they support the sketch during the presentation.

When putting matting boards around the presentation sketch, they should be much wider than the drawing or water colour so that ambient light from behind is modified by a greater expanse of black or dark matting board.

"Transparency sketches" edited from emails by Richard Millard

There are, of course, a number of CAD and drawing programs available for computers which can be used to make presentations to the clients. However, I have no experience with them, so perhaps some one will give pointers on how to make use of these electronic means of presentation.

Cartooning for acute angles

When you are moving from the sketch design to the cartoon lines for panels, you can prevent some leading difficulties. If you have shapes that join at acute angles, you can alter the cartoon lines from the design to make the leading simpler.

Say you have two balls touching in the design. You can continue the design of the cartoon so the cut lines intersect or touch each other. This makes for extremely acute angles in the cutting of the cames. Two balls touching in the presentation drawing will not look the same if leaded that way. Therefore, make the edges of the balls just a few millimetres separate in the cartoon, and the cames will pass each other, just touching, retaining the appearance of the presentation drawing, rather than the appearance of overlapping.

To do this, you separate the lines by the thickness of the came you will be using for that area. If you are using 6mm came, the cut lines should be just less than that distance apart. This will allow the cames to go around each shape and the flanges of the came will just overlap. This makes for quick leading and a clean appearance.

Making copies

Using a photocopier is not always the best way to provide copies or reproduce the cut lines. At significant enlargements, there is distortion of the lines and the cut lines are much too wide to be practical cutting guides. A much older instrument useful for this kind of reproduction is a pounce wheel. These are still made and are available. The pounce wheel comes from a time before photocopying or carbon papers. It gets its name from its use together with a pounce bag. In the past the pounce wheel would make holes through the paper or card along the design lines. The paper or card is put over the material which is to have the image copied onto it. A small bag of black powder would be dabbed (pounced) on the cover paper leaving black dots on the surface below. These could then be used to trace the same image many times on what ever medium was being used.

To copy part of one stage of a design onto a new one without using tracing or carbon papers you only need to layer a new sheet of paper under the current design and run the pounce wheel over the parts you want to copy. As you move the wheel along, it punctures the top layer and into the lower layer. Normally, the puncture marks are all that are needed to be able to reproduce the original lines.

You can also use the wheel to create mirror images by running the pounce wheel over the card, turn the card over and draw using the puncture marks.

You can get symmetrical images too, by folding the paper along the centre line and running the pounce wheel over the existing line. Unfold the paper and use the puncture marks to make lines symmetrical on each side.

Avoid tapering pieces in the design.

You can't use long tapered pieces in larger panels, without modification for the structural reasons outlined previously.

Also you can't make a neat termination by joining half a dozen tapers at one point. Your piece will not look exactly what it looks like when you drew it out with a pencil. You can pencil in a termination with six points, ending at one place and it may look good, but try drawing it in with a felt tip pen almost 6mm wide, which allows for what solder or foil will cover, and see what that point looks like then. You won't be pleased with the large blob at the termination.


No one can teach one easy fix for everything you will encounter, so the answer starts with the design - before you cut and foil, or fit the came to the glass.

Art is not about the physical placement of what you see in your mind, as much as it is about the "illusion" you are creating that you want others to see. That starts with the design, and avoiding something that you know is going to give you a problem in building or viewing the final piece.


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