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darkening the violin wood


Peter White

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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/i.

And with regard to this thread, I can confirm that the one or two recent dings on my daughter's current ( goffriller) loaner ( very minor, don't tell anyone!) reveal that the wood colour below the ground is as white as a new instrument.

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One of my favorite instrument museums was the late departed one at the V&A....One thing that stood in my mind were some pre Strad English viols with wood as white as if it were varnished with  a commercial product last week.

Del Gesu instruments are quite interesting re wood and ground color.....some of the examples at the Bergen exhibition  looked like pale failed attempts to emulate del Gesu ground color  but they were the real thing. 

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Are we talking about the spruce or the maple? Because it seems to me that the spruce plate could quickly darken even by simply staying in the shop for few days while other things were done. Maple on the other hand need quite more exposure to yellow.

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Gofriller must have treated the wood to prevent the natural darkening and opacification, apparently ;)

As we don't have any good photos or examples of fresh, new Cremonese instruments, it's speculation what the ground looked like new. Personally, the idea that makes most sense to me is that age and perhaps some sun (in the original drying, or any time thereafter) creates the golden loveliness. Many years ago I bought a new Collings guitar. It was too pale for my taste, so I carefully sunned it for a couple of days, and it made a world of difference.

I really don't have any strongly held opinions about Cremonese staining or not. It won't affect what I do. It just seems like another in the parade of "Cremones Secrets", and should have more bulletproof evidence and logic before it can be accepted as fact.

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If I understand the authors of Stradivari Varnish correctly, they believe that Stradivari sealed (they use the term "Impregnated" ) the wood and then he applied a liquid or paste stain, perhaps colored in anticipation of the final layer of colored varnish. Therefore, it is possible that the wood is white (or whitish) under the "impregnation."  There is some ambiguity about the timing of the sealing and the staining, but the authors seem to have used every advanced techological and chemical analysis to reveal this stained layer, probably above the sealer "impregnation."  I do not take a position on this.  I am only reporting what they have written, as far as I understand the spectrographic science and chemistry. I should have made it clearer in my original post that the stain probably was applied after the sealing. There is pretty persuasive evidence for the existence of this stain layer. Maybe somone who has the book can comment on my summary of the conclusions?

Thanks for your interest.  Peter White

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A few points to ponder.  Rabit urine, well that's just an amonia source isn't it?    So why not just use household amonia?    ahh peace on it.     Most makers seem to like tanning the wood with UV which gives a light tan color to the wood.   Looking at pics of cremona violins, the wood really doesn't look all that dark to me but I've never seen one in person.   Varnish can be made highly colored even in a thin layer.   Original varnish layers may not have been all that thin as there are some good closeups of Le Messie where you can clearly see the thickness of the layer.    A weak subtle stain can enhance flame in curly maple but a strong stain wil burn it in and kill the chatoyance.  

 

Sorry you got that wrong. The way it was used by Aubert on bridges yes, (see base blog) but not how I use it.

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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.

 

I would agree with this. It is possible that Strad stained the wood, but it is equally possible that it turned that color with age. This comes back to the old question. Do we want our varnished to look like, or be like Cremonese varnishes? The two may not be compatable if we are varnishing instruments today.

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This thread got me to drag out my oldest wood of known age, and also the newest, for comparison. I also have some other wood that appears to be fairly old, and got that out too. These were all in my woodpile, stored indoors in low light.

I planed a bit of the edge on a skew, to show up how the wood darkens through the thickness. The new wood I didn't plane.

post-25192-0-20835800-1370621614_thumb.jpg

To get a better comparison, I sampled out part of the photo where the lightest areas were, and pasted them on the new wood.

There does appear to be some darkening related to air exposure. The endgrain (unsealed) shows the most depth of darkening, and other surfaces only show very shallow darkening. However, even the interior is significantly darker than new wood, implying that chemical darkening processes can go on without significant airflow.

This is consistent with my thermal processing experience, where I go to significant effort to exclude air. Before I upgraded my equipment, there was some air in the process, and resulted in extreme surface darkening. Without air, the color is more uniform throughout. In theory, the chemical reactions that darken the wood in the chamber should be happening all the time at room temperature... but at a MUCH slower rate.

edit: on the middle sample, the lower edge had been trimmed recently, which is why there is no surface darkening on that edge.

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I think Glenn Wood made a good point in that the darkening  and oxidation of wood in just indirect light and air  goes to a depth of around 1mm per century.It also makes the wood opaque to light trammission. I have no reason to disagree with him,the effect can be easily seen with old tonewood of a nice colour ,which disappears with a simple shave of a plane.

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I would agree with this. It is possible that Strad stained the wood, but it is equally possible that it turned that color with age. This comes back to the old question. Do we want our varnished to look like, or be like Cremonese varnishes? The two may not be compatable if we are varnishing instruments today.

 When I see a nice antiqued Vuillaume, I see what old Cremonese varnish had worn away to after a century, reproduced with a much harder finish. It's a snapshot of a century of wear on the soft varnish of the old masters. Nowadays we're making snapshots of 300 years of wear, and if we're using soft varnish, or a simulacrum of the classical varnish, all of our fiddles will soon be nude, caught on stage with their varnish down to the wood.

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I believe spruce should darken (oxidise) much more along the years than maple, even after varnishing. Have you noticed Cremonese violins show darker tops than backs?

I planed off a piece of maple that I have that's ~30 years old, and found almost no thickness of darkening, even at the unsealed endgrain. I don't have any good way to know if there has been overall darkening throughout, but I doubt there has been much. On the other hand, I had a set of maple that probably was pretty old that I used on #5, and there was significant darkening for 1 - 2 mm thickness. So I guess it varies.

I also agree that spruce tops appear to go darker more quickly than maple backs.

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Well, I realize that Stradivari Varnish costs about 600 bucks, and much of the book is filled with complicated material, I think that in time many serious violin makers will consult this book, look at the photographic evidence for a stain layer above the sealer, and begin to experiment with stain layers to reproduce the intensity of the flame and the beauty of classical varnish, and discover the benefits (maybe in tone and appearance and time savings) of this technique as outlined by Stefan-Peter Greiner and others.  In the meantime you might google his website and take a look at his work.  I decided to write to him directly and I will ask some of the chemists at the university where I teach--as well as material scientists, what they think.  I am interested in the process of searching and inquiring, as well as in the more practical aspects of making violins. I think the historical search is fascinating, and if we did ever find out all the answers, the art of violin making would be boring.

Thanks for your interest. 

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Hi LinkMan,  ask and ye shall receive.  Here's the beef! (I remember those commercials,  she was cool :D)

Here we have a cooked varnish with no coloring materials added, on top of white (un-darkened) spruce.  The varnish layer is something near a tenth of a mm maybe slightly more.  Something interesting I notice in the closeup photo is the bright line of light that seems to glow just under the varnish layer.   As I recall I think there is a ground on it but that only seals and in maple it enhances chatoyance but it doesn't darken significantly. This pic was taken in sunlight.  Inside in room light it's less interesing, more of a brown but I think that pic is on my other computer.     Don't ask me if I can repeat the recipe...  ;)    I hope I can.

 

P.S.  Found the pic of it in normal room lighting.  Third pic below. 

post-31367-0-65073900-1370660032_thumb.jpg

post-31367-0-19457700-1370660334_thumb.jpg

post-31367-0-58718400-1370660689_thumb.jpg

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