A colleague from the Netherlands asks us something really useful:

As a novice, I have a burning question.

Say I experiment with your technique: so I paint an undercoat and then copy-trace the main lines from the design.

Now what if I make a mistake during tracing. What is the best procedure for correcting this mistake without ruining the work I’ve already done?”

This is such an excellent question, we’ll approach the answer from several different directions.

First, though, let’s step back a bit and give some context to the question.

All your tracing and shading, front and back, in a single firing

Yes, we discuss and demonstrate this a lot. Not because it’s the only way to paint stained glass. Rather because when you master this technique, many other techniques are easy by comparison.

And also because so many people have been told, “It’s impossible!”.

Well it isn’t.

Here’s what we mean:

1. Paint an undercoat which primes the surface of the glass
2. With the design on top of the glass, lightly trace the main lines
3. With the design on one side where you can see it, strengthen the main lines as needed
4. When these are dry, cover the whole surface of the glass with a light overcoat of paint
5. While this overcoat is wet, take your badger blender and turn these precise lines into blurred lines and shadows
6. Now with your tracing brush again, reinstate precise lines where needed and also add fine details
7. Make highlights as needed
8. Paint on the back as needed
9. Use oil-based paint on the front as needed
10. Make new highlights as needed
11. Fire your glass

So right until step 9, you’re using water-based glass paint.

And the glass is only fired once.

Why?

As I mentioned earlier, if you learn this approach, you’ll find most other things easy by comparison.

More to the point, you’ll do those other things with greater confidence and skill.

So when you decide that a particular design doesn’t need an undercoat but just needs really exact and bold copy-tracing, you’ll do this much better because of what else you also know.

See what you’ve done by learning “our” approach is you’ve learned how to observe and concentrate better, and these qualities are really essential for glass painting.

But there’s more to it than even this.

And it’s not even that this once-firing technique can save you time and money. Of course it can and will. But these are small benefits by comparison.

Yes, the really big benefit is that, when you only fire at the end, you’re able to continue responding to and adjusting all the different values of light and dark which are on your glass – whereas if you fire your trace lines and then do the shading, well, you’re stuck with them, aren’t you?

Sometimes that’s a good thing. Say when geometry and intense symmetry are involved. Yes? This is where the “trace/fire” approach (as we call it) – i.e. where you trace the lines then fire them in the kiln – is excellent.

But what about more fluid things with texture like clouds, fields, petals, hands, eyes … the list is endless. What about them, and the gentle fluidity they often want?

Ancient knowledge and the Industrial Revolution

Most likely the “trace/fire” approach became dominant during the Industrial Revolution.

Imagine all the activity in those big 19th century studios … all those church windows which had to be produced incredibly quickly and almost as if they were on a conveyor belt in order for the studio to return a profit.

Here’s where the temptation arose to abandon ancient knowledge in order to “simplify” the means of production.

Another casualty was oil-based painting. You see, if you’re just using water-based trace lines with the right amount of gum Arabic, then you can afford a certain amount of rough handling of the pieces without risking any damage to them. You can even pile them up on top of one another on the way to the kiln. Believe me, I’ve worked in a big studio – not a nineteenth century one of course – and that’s exactly what happens. So we weren’t allowed to use oil …

Because the moment you add oil (which doesn’t dry, and doesn’t contain gum), then you’ve got to slow down and pay attention.

Which we think is usually a very good thing.

I mean, are we painting glass or are we trying to imitate a machine that prints paint on glass?

You decide that question and its consequences for yourself.

So anyone who’s interested in the idea of painting on glass (as opposed to behaving like a mechanical printer) can find loads of information right here on this web site. Just browse, read, experiment and enjoy.

And now to return to the excellent question …

Mistakes happen – but are they really unacceptable?

We’ve already mentioned an important part of the answer. You see if you’re not painting something that requires mechanical precision, the first thing is, it’s essential to be realistic about what is acceptable and what isn’t.

Say there’s some variation in the darkness or the thickness of a particular line.

• Think hard: does this really matter?

Imagine the window in context: this piece will be surrounded by many others, and you have to consider whether it will be seen from close-up or from a distance – this too makes an important difference.

Here’s what I mean. When you next can, go into a church, find some painted stained glass, and choose some pieces to look at ruthlessly and analytically. I’ll bet you start to see flaws.

But the point is, it’s oten wrong to call them flaws. These variations are part of their humanity. Think of silhouetted letters where some parts of the script are lighter than others. Close-up, this is a flaw. At a distance, there’s a gentle undulation.

Now believe me here, David and I are the last people on earth to tolerate anything that’s careless or messy.

But we know very well that, when you’re staring hard at a piece on a light box, your eyes and your mind will tend to pick up on all kinds of small things which aren’t really important.

So of course be critical but don’t let yourself be distracted by over-criticism. There comes a point at which finding fault with oneself is actually the lazy thing to do. Sometimes better to pay attention and advance and see how well – from a “mistake” – it’s possible to finish.

Mistakes happen – so keep your copy-tracing light

And here’s another benefit of our approach: copy-trace lightly and when you come to reinforce, chances are the mistake won’t show. In fact chances are it’s no more a “mistake” than the light sketch marks we make in pencil when preparing to draw or practice a line on paper.

But you must keep your copy-tracing light and dry (not too much water in the brush).

Contrast this with the tradional “trace/fire” apprach. Here you’re meant to do your stroke in one go, without going over it again (“because that’s what causes blistering” – what rubbish!). So there you are, with the glass on top of your design, painting dark traced lines (and probably feeling quite anxious because you’vegot to get it right in one go).

Now ask yourself this: done this way, isn’t pretty much every stroke a mistake?

Here’s why: because, with your glass on top of the design, it’s nearly impossible to assess correctly your density and thickness of line.

With our approach by contrast, you first “sketch” the main lines. Then you put the design on one side. And then you build up the main lines as required.

And here you’re focussing on the line on top of the glass.

So you’re paying attention to what’s really important.

You’re much less likely to make mistakes. If you do, consider this next point here …

Mistakes happen – so consider what you’ll do next

Here you are, copy-tracing a line, and something has gone wrong. Another thing to consider is this:

• Now you need to think through everything else you will do with this piece of glass.

So suppose you’re planning on going right through to step 10 above – that is, you’ll be softening, reinforcing, painting on the back, and painting with oil …

You have to ask yourself: will anyone know about what’s just gone wrong, or is it rather like a footprint on the sand that the incoming tide will wash away?

Only you can decide.

Decide wrongly, and everyone will be required to live with your error for 100 years or more.

Decide correctly, and your painted stained glass window will possess some individual life of its own.

Mistakes happen – and what can you learn from them?

Say it’s genuinely something unacceptable: a blob of paint drips onto a painted nose.

Maybe you do need to start again. It happens. It happens to all of us.

The thing is, that blob is actually information, and the question is, What is it telling you?

Figure that out, and you’ll paint better next time.

So what might it be telling you?

Probably, something went wrong on your palette:

• Did you load too much paint onto your brush?
• Is the paint too wet?
• Is the paint badly mixed?

You see, it’s no use deciding to rub out your work and start again unless you also figure out what went wrong.

See, rubbing things out sometimes becomes a distraction from not thinking.

People often think just because they’ve started again, they somehow deserve things to go right next time.

But life’s not like that. And glass painting isn’t either. You must change something.

And no, there isn’t a magic formula, a silver bullet: you must observe with your own eyes and think for yourself. That is one of the many joys of glass painting: it demands such focus from you. And once you start to give it that focus, you’ll see improvements every time you paint.

So don’t be too rough on yourself when serious mistakes occur. Remember you’re a glass painter (not a mechanical printing-device). Thank goodness.

I hope this all helps.

All the best,P.S. Remember the only way you can be sure of getting all the tips we publish is for you to join our free email newsletter. If you don’t, you’re missing out. Now more than ever it’s a good idea to improve your glass painting technique and keep it at its best. It’s quick, easy and free to join. We never share your details with anyone else. Start here today.