Stained Glass Tracing with Vinegar

Sue Sills wrote and asked us about mixing glass paint with white vinegar:

I have only used water and gum for mixing tracing paint so far.

But I was recently told that you can use white vinegar instead of water and that it stopped the paint from drying out so quickly, thus making it better for tracing lines.

Do you know if this is so?

The benefit of vinegar tracing

Now it’s certainly possible to mix glass paint with white vinegar, and trace with it onto stained glass.

But many books suggest a different virtue than stopping the paint from quickly drying out.

Here, for example, is Albinus Elskus:

When the finished [vinegar] tracing is drying out, the white vinegar will harden the paint and render it water-repellent.

This allows you to apply a coat of water-based matting color before firing in the tracing and so save one firing time” (The Art of Painting on Glass, Albinus Elskus, The Glass Press, 1980, p. 25)

So the received opinion on the virtue of vinegar-based tracing paint is that it allows you to trace and matt in just one firing.

We’ll return to this opinion in a moment.

For now, let’s just consider the question whether vinegar-based glass paint actually slows down the drying time.

In our experience, this is not the case.

Rather, what it does to is to increase the hardness of dried (unfired) glass paint.

It’s exactly this property which – as Elskus suggests – allows you to matt over it with water-based paint, and thus save yourself a firing.

A small difficulty with vinegar tracing

But you also need to know that dried vinegar-based tracing paint is far more difficult to reconstitute and re-use than dried water-based tracing paint.

This is the case even when you’re just working with a teaspoonful of glass paint (and not the 3 ounce lump that we definitely recommend when you use Reusche tracing paint mixed with water).

So it wouldn’t be a good idea to mix up anything more than a teaspoonful at a time.

In part-time conclusion: vinegar makes unfired glass paint more resistant to water, but it doesn’t decrease the speed with which paint dries.

I hope that answers the main point that Sue raised when she wrote to us.

The uses of vinegar tracing

Now let’s return to the question of water-based matting over unfired vinegar-based tracing.

And let’s be absolutely clear that this is a perfectly correct technique.

It works.

Therefore, if you’re restoring a broken piece of painted stained glass, and this is how the broken piece was originally made, then this is of course the technique that you should master and use.

And what about your own stained glass painting that you’ve designed yourself?

Here’s what we think.

If you wish to preserve an absolutely stark line – in other words, if this is what is demanded by your design – then, to save a firing, you can indeed use a vinegar-based mixture, and, once it’s dry, apply and work a water-based matt.

The vinegar hardens the trace so that you can blend the subsequent matt without softening or destroying the trace.

However, what you learn from our studio painting manual (free chapter here) is a different approach to line and shadow.

And, with this different approach, you also learn a different set of glass painting techniques.

Indeed, you learn how to throw received opinion on its head.

You learn how to shade and matt before you trace, and then, even before firing your water-based matting and tracing, you discover how to trace and matt with oil-based paint.

And then you get to fire your paint just once!

If it’s absolutely rigid lines you’re after, then, with our approach, you just trace them on with water-based paint once you’ve finished your water-based shading. (This is all covered in Part 3.)

And as you discover in various glass painting projects like the owls, you can also paint a water-based matt on the back of a piece of unfired glass painting.

Really, therefore, you can use water-based paint to trace and shade in a single firing and build up as much density of tone as you could possibly wish. (So we do wonder, what’s the point of vinegar?)

Water tracing vs. vinegar tracing

Now it’s not that one approach is absolutely superior to the other.

As we suggested earlier, it depends on the requirements of your design.

For our own part, we are uninspired by the starkness of line as found in so much stained glass painting – the very starkness that is preserved by vinegar-based tracing coupled with water-based matting.

Of course we accept that starkness of line is wonderful in the right place.

Just consider medieval stained glass faces, for example.

But the stark (unsoftened) tracing line is just one tracing technique amongst hundreds.

Starkness of line should not be represented (and even worshipped) as the way in which “stained glass tracing” is done.

And yet this is exactly what happens in stained glass studios and art colleges across the world.

This dogma then feeds back into the way in which stained glass designs are conceived and prepared.

So a pre-conception about (just one) stained glass painting technique then slowly but surely begins to limit the possibilities of the craft as a whole.

Really, though, stained glass designers should design with the building and the clients in mind, and only then (when the design has been agreed) remember, discover or invent an appropriate technique to use.

Stained glass painting techniques are merely means to an end.

Therefore their true purpose is to help the realization of a design and artistic vision.

But ignorance and secrecy often permit them to constrain the act of design – and this is such a pity.

That’s why we take care to explain the technique of “softened lines”, as we describe them – painted marks on glass which are half-way between starkness and shadow.

It’s simply another technique to add to your repertoire – even if received opinion says it can’t be done.

“But isn’t it Dangerous?”

With layer upon layer of unfired water-based glass paint (as you learn from us), there’s certainly a risk that, if your attention wanders, you can wreck the piece.

In that case you’ll need to start again.

But we find that this risk increases our attention.

We find it also increases the attention of people who learn to paint like this.

If you trace a line and then fix it in such a way that it’s difficult or impossible to shift it – either by using vinegar on the one hand or by firing it in the kiln on the other – then you can afford to be careless with your shading and highlighting.

And that’s a pity.

On the other hand, if you paint stained glass as we suggest, you’ll have the joy of knowing that each layer of unfired paint is still responsive to your every brush-stroke – right up to the moment that you put the glass in the kiln and flick the switch.

This calls for great skill and sensitivity, but since when is that a bad thing?

12 thoughts on “Stained Glass Tracing with Vinegar

  1. Thanks, Stephen, for that informative post. I’m sure I’m not the only one who’s been missing your regular posts. Is there any possibility of a feature on some of the fascinating projects you’ve been working on?


  2. I like reading your information on glass painting. I’ve been painting on glass for two years now, and I find it very interesting.

  3. I, too, began painting with vinegar from exposure to Albinus’ book, but I later abandonded vinegar trace in favor of oil trace. Oil does dry slower and it can also be matted over with water. However you cannot recreate the lovely blurred line effect which you demonstrate so masterfully in your book – a wonderful technique!

    My question, related to vinegar, references ancient techniques. Theophilus documents mixing paint with wine (or urine) in his 12th C. treatise.

    Both of these mediums are acidic & sticky – which probably made them a logical choice.

    Would old wine, which was turning to vinegar, then be a possible origin of the vinegar technique? Have you come across any documentation for when vinegar was first used – surely it didn’t begin with Albinus?

    Other books which I’ve read from the 1800’s mention using thickened turpentine as a tracing medium. Personally I’ve been curious what mediums the medallion painters of the Lowlands were using in the 15th C. The lines they were able to achieve are so fine! Not something you could achieve with vinegar for sure. Personally, I had inconsistent results when I tried to matt over vinegar trace which I now attribute to not getting the right amount of gum arabic in the mix.


  4. I like using vinegar. It gives a ‘crisper’ line. It dries much harder. You can matt over with water. If you have enough gum in the water mix, you can then put a third layer on top using denatured alcohol. This technique works well – if you work fast enough. If you do not work quickly or if you over-work you piece, you can mess it up. It can be done, but it is not an easy technique to learn.

    I also like to matt with vinegar. I had one particular application where I was painting a water fall. I needed mist rising up at the bottom of the water fall. I put down a vinegar matt and let it dry. Then I spritzed the piece with window cleaner. The droplets of cleaner dissolved the matt. After it dried, I used my badger to brush off the paint. The result was hundreds of droplets of clear unpainted glass – perfect for rising mist!

    It is important to learn ALL the various techniques. I keep a scientific log to record my results. The techniques that I use on one job may not be the right technique for the next job. With my log, I have a vast assortment of techniques that I can choose from.

    By the way, Kenneth Leap’s work is incredible.

    For Jeff Hitch, try mixing your silver stain with oil. The slower drying time allows you to badger a nice matt. The biggest problem with silver stain is making sure you are painting on the correct side of the glass. Do a test with using one piece of glass. Cut it in half. Apply silver stain to the front of one piece and to the back of the other. Fire it. You will see what I mean by the right side of the glass.

    Laura Goff Parham

  5. We’ve just received this comment from Bill Disbro, Jamestown, New York:

    “I took a workshop in 2008 from Debora Coombs at the American Glass Guild conference at which I learned to add Propylene Glycol instead of water to Reusche Best Black. Once the mixture has set for at least 2 weeks, perhaps a little water is added to get the consistency desired, lines can be drawn with ink pens, including Hunt’s Crow Quill pens that give a line as fine and lively as can be done in ink. The trace also has the long pull rather than the short stroke one may think. It’s truly a marvelous material to work with and cross-hatch drawing can done that is as complicated as in ink. (The longer the trace and propylene glycol mix before using the better. Mix a batch, put it on the shelf and forget about it for several months!)”

    We’ve just prepared a batch ourselves and can’t wait to start our tests in a fortnight or so.

    We’ll document and publish our results of course.

    To finish, here’s another excellent idea from Bill:

    “Using this mixture of glycol/best black (or any color I suppose) put on rubber gloves and finger paint with it on glass. One can get fantastic textures easily and rubber tipped tools can be used to erase areas/lines not wanted. One of the best things I found is: take only the point of rubber gloved finger and touch a dab of trace then repeat touching area of glass – a fantastic mechanical pattern is created quickly – background areas, etc.”

    All our thanks to Debora and Bill.

  6. I am curious to know if you tried the propylene glycol?
    Also, I am wondering if there are specific properties that make one oil more suitable than another – massage oil was mentioned, which I guess might be almond oil, but why lavender and clove or sandalwood, as opposed to olive oil for example?

    • Hello Lynette,
      Thanks for your message.
      I’ve only done some limited tests with propylene glycol. If my memory is correct, Deborah Coombs is the person to contact about this.
      You also ask about oils.
      And it mainly depends on whether you’re using glass paint or silver stain.
      Also on your means of applying the paint to the glass.
      With glass paint and a brush, oil of lavender on its own is fine; or – if you are extremely careful, oil of tar.
      With glass paint and a nib, it’s oil of clove, diluted as necessary with some oil of lavender.
      With silver stain and a brush, it’s oil of sandalwood, diluted as necessary with some oil of lavender.
      I’m sure other oils will also work but you must be careful of combustion/flammability and also of the fumes.
      I just don’t know enough chemistry to hazard a guess about the specific properties of any particular oil which makes it suitable.
      But I hope this answer helps.
      All the best,

  7. Hello Stephen,

    I just received an inquiry about painting with propylene glycol from someone who studied with you recently (Hassan) and ended up reading this post for the first time. I wondered if you’d like a copy of my student notes explaining how to mix, slake and thin the pg mix ready for use? I cannot find anywhere to attach the file but you can email me and I’ll send it by return.

    I refer students to you often and love that fact that you’re willing to share techniques so broadly via the Internet (and do it so brilliantly!).

    I’m not nearly as computer-savvy as you two but very willing to share. I’m extremely enthusiastic to see quite a few strong younger stained glass painters emerging. I think the AGG conferences may have helped. If Ken leap plans an English Invasion for the 2014 conference (possibly at Bryn Athen in NJ), would you come? I’ve been talking to Kathy Jordan about doing a propylene glycol workshop as part of the pre-conference events.

    If you’d like to share my notes I’d be happy to send them to you just email me.

    All the best, and keep up the fabulous work!

    • Hi Debora,

      Thanks for your kind offer of help, and yes, I’d love to accept, because I know you know a whole lot about this medium. Please let me just consider how best to do this. I am on holiday for 10 days right now. I will write to you when I get back.

      Thank you again, and all the best,

      P.S. We definitely plan to come and meet you and Kathy and Ken as soon as we possibly can. (I’m hoping to meet Kathy sooner – over here – if that comes off.)

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