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darkening the violin wood


Peter White

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In the last decade there has been a tremendous amount of scientific research on classical Italian violin varnish, particularly on Stradivari's varnish methods. Two studies, done with most of the same equipment, come up with very different conclusions. Bruce Tai in the 2007 VSA papers and the recent Stradivari Varnish book by Grenier and others differ in the number of coats or layers Stradivari and other contemporary makers used.  I tend to agree with the very recent Stradivari Varnish book that says there were probably four steps in Strad's varnish method: sealing, staining (darkening), one clear coat and one color coat. But I have some questions about this, provoked in part by Mr. Hargrave's use of rabbit urine and UV light, about the science and about a reasonable method of varnishing with resin and linseed oil.

(1) were there 2 coats of varnish or 11 coats, the conflict raised by the two studies mentioned above

(2) If Strad used multiple coats of resin and linseed oil varnish, how did he have time to sun dry somewhere around 1300 instruments in cloudy and rainey Cremona ?

(3) If he used only two coats as suggested by Stradivari Varnish, do you makers really think that one color coat of vermillion colored varnish would produce a vibrant red violin on white wood?

(4) Therefore Strad had to have darkened the wood to produce the flame, the color, and quantity of violins he made.

(5) Does anyone have a reasonable (scientific or practical) method of darkening the wood before varnishing?

I appreciate all the work that has gone into these studies, and the practical value of Mr. Hargrave's use of urine and UV, but no one as far as I know can determine how Stradivari darkened his wood--chemicals, dyes, stains, urine? I have 35 years of experience with resin and linseed oil varnish, and I fail to see how two coats of this varnish could produce anything like a classical finish, unless (a) the wood was darkened considerably first and (B) the color agent was very powerful in intensity and other characteristics.

One of the reaasons I raise these questions is because multiple coats of linseed oil varnish will reduce volume and tone, additionally it is too time consuming, Glazing is not the answer. So, interestingly, the so-called "secret" to Strad's varnish is that there was very little varnish!!!

Help me out on this one makers, please.  Thanks. Peter White

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It's a matter of reading the book, and having some varnish experience.

1. It is concerned with the different types of layers. How can you differentiate whether 11 super thin coats of oil went on in one of the layers, or 2? If they are the same material, they will not delineate, especially after polishing.

2. With a 4-1 resin to oil ratio, a coat of oil will be dry in less than 24 hours.

3. There is a layer of floating red pigment directly after the ground layer, which helps throw light, and establish the tone of the color of the instrument. Also, if you're ballsy, a single layer of red can be as saturated as you can imagine making it. Handling it gracefully is the problem

4. He difinitely did. To MikeC, sometimes a Bergonzi is less than Cremonese-dark, I think, but those classical Crems are beautifully tanned.

5. There are dozens and dozens of reasonable, scientific methods for darkening the wood. Picking what you like, or what you assume is historically sound, is the quest of the maker.

 

As for cloudy Cremona, I've always thought it reasonable that one would make during the winter months, hang instruments through the sunny months, and then varnish the next winter, as you're making again. Not only sun oxidizes. Air, lamp smoke, and time help too.

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I'm also suspicious of the ability to identify layers of varnish.

 

My current method involves putting down a layer of moderately colored cooked resin oil varnish, then applying many 'coats' of a madder/cochineal colored alcohol tincture. The tincture does not dissolve my varnish but incorporates with it and the colors intensify with subsequent applications.

 

I believe there is an historical basis to justify the use of  tincture as a colorant in Cremonese varnish. If one examines the endoscope photos of the Cannone, (middle of page) Del Gesus' famous violin that was used by Pagannini, the staining on the inside of the instrument shows a very thin colored liquid. Very likely a colored tincture.

 

In this way a single coat of varnish can be made with as much color saturation as required. However using only transparent colors results in a 'stained glass' effect which is not attractive. Some translucent pigments are necessary to give the varnish some 'weight'.

 

In my opinion as soon as the wood is substantially darkened it's reflective properties are diminished and the depth and brilliance are also diminished.

 

 

Oded

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There are two distinct and different effects between coloring the wood or the varnish.

 

Obviously a dark colored varnish will result in a dark appearance. The nature of that dark color depends on the transparency of the film.

 

A transparent red film filters out the yellow and blue colors but allows the red to penetrate to the wood where it is reflected back.

 

If the wood is a strong reflector the red color will emerge as a brilliant dazzling color but if the wood's ability to reflect has been compromised, then the quality and amount of reflected color is diminished, limiting the possibility of any brilliance, intensity and depth.

 

So, while coloring the bare wood and coloring the varnish may result in two instruments with the same color value, the appearance of the two films will be dramatically different depending on the reflective properties of the wood.

 

Oded

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When treating the inside of an instrument to protect it from bugs and moisture, my process darkens the wood as well.

Watching a miniscule shaving of a Strad button being taken off to replace a cracked ebony cap, in at least that one instance, the wood was not as dark as the surface material. There hadn't been a button graft, to our collective eyes...

If something is 300 years old but sealed with varnish, how would the wood beneath oxidize, I've wondered. My conclusion has been that the wood was allowed to sun, or was treated to darken it.

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My guess, and it is a guess, is that every possible way of entering color in was used, and this involved many more additional steps, which separated the Masters from the rest.

Time consuming, and costly, but the clients were Kings, so it was not a problem, and Kings must have he best.

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I started this thread because Brigitte Brandmair and Stefan-Peter Greiner in Stradivari Varnish: Scientific Analysis of the Finishing Technique on Selected Instruments

clearly show that Stradivari used some sort of stain on the wood that contained the elements Potassium, Chlorine and Phosphorus, but the authors do not provide any specific information about staining or darkening of the wood.  Identification of the elements found in the stain layer is not the same as saying what Stradivari used to stain the wood. If you have read this book, you can not doubt that the wood was stained.  This "darkening" of the wood made it possible for the application of very little varnish.  Although one maker replied that there are dozens of methods of darkening the wood, he did not volunteer to name any of the ones he has found to be safe in the long run and/or containing the elements found in the Stradivari Varnish book.  I have read the book, I have 35 years of experience with oil varnish, I have heard of many methods of darkening the wood, but all of these have had other experts declaring them harmful to the wood, dangerous to the user, or clearly producing unsightly effects.  I do not expect any violin maker to reveal his or her methods, but I do ask that others (having read the book) comment on what they think might have been the stain (maybe in liquid form the authors say) Stradivari used. Some generous folks might even volunteer to reveal what they believe Strad used and what they currently use. I use the term stain, darkening, and dying the wood interchangably because the authors don't know what it was or how it was applied.

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It isn't obvious to me, other than the effects of 300 years of age. There was a similar discussion in this thread:http://www.maestronet.com/forum/index.php?/topic/324656-new-scratches-in-old-instruments/Pay particular attention to the photo posted by Bruce Carlson, showing nicely tanned shavings from INSIDE of a Guarneri.

You're wrong.

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I am absolutely correct: I said it isn't obvious to me. I didn't say it wasn't so. I admit that I have not read up on the subject. However, as a skeptic, it would be quite convincing to see an example of 300 year old varnished wood that looks like it was done recently (and proposing the Messiah as an example sortof defeats the staining argument).

Can someone summarize the evidence for staining for me, other than the identification of some elements? It is curious to me that none of the experienced posters in the referenced thread mentioned staining.

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to David Beard:  A reasonable statement or question you have raised, and so did my violin making friends, but I went back to the book and the authors talk about layers as coats. In other words, they use the terms interchangeably--a layer means a coat.  I had to read and re-read to find this. But I am pretty sure the authors are talking about what we all call coats--different applications.

However, I should never have mentioned this conflict about coats because my real interest is in the stain they found.  That is key in my mind.

Thanks.

Peter

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It isn't obvious to me, other than the effects of 300 years of age.

Nor has staining been obvious to me. Actually, I've been quite surprised at how light-colored the wood can be when numerous layers of dirt-impregnated polish have been cleaned away, or when there is a fresh chip or other fresh varnish damage.

 

My impression was that the color wasn't any more than one would expect from normal aging. Maybe even lighter than that, as if the wood had been protected from the time-induced darkening one would see on a piece of raw wood.

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You're wrong.

John, It isnt obvious to me either ,many Cremonese instruments ive seen were pretty light at wood level compared to instruments from other schools,with some exceptions such as one or two of the Guarneri family,that appear to have used some sort of staining or chemical treatment on some of their instrument.

Indirect visible light can have as much  darkening effect over a long period as a shorter period of sunlight /UV,it can also penetrate wood further and varnish .

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I became convinced about this when my daughter had a GB Ceruti on loan for a while. It had a fairly typical wear pattern, and the vast majority of the exposed wood was a dirty-creamy white colour. But there were remnants of a golden colour ground layer at the edges of the wear. I read that as GB trying to emulate the earlier Cremonese ground colour, but with it "on" rather than "in" the wood, and becoming removed as the varnish wore. This instrument had all the layers of polish on it they David describes, but the wood wasn't the typical golden colour associated with classical Cremonese. I have pictures somewhere if anyone's interested. I may even have posted them on here before. And again, when you see the beautiful golden colour of the exposed wood on an instrument like the viotti strad it seems inconceivable to me that this colouring was not introduced deliberately.

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