darkening the violin wood

[Janito]

Hi Joe,

 

If I recall correctly, Brandmair did mention specific proteins (casein, collagen and ovalbumin) with respect to at least two samples.

 

John

 

Lunch scraps, perhaps.

[Patrick KREIT]

Peter White

 

To use casein glue as sizing, there are two possibilities:

 

- Either casein made with slaked lime that can be used on the inside or outside of the sounding box. However, casein with lime must be used carefully, for, according to its pH, it can react with the wood and confer an undesirable color: it depends on what you want to obtain. Test the product on pieces of wood before applying it to the violin.

 

- Or casein with borax, which is perfectly translucid, has no drawbacks, and can likewise be used inside and outside the sounding box.

 

Drain the non-fat fromage blanc.

Add the lime or borax (10% to 20% of the weight of the cheese) and mix well with a wooden spatula.

When the sizing is ready, it turns slightly gray and gives off a faint odor of ammonia.

Add linseed oil (5% of the weight of the cheese). Stir well to form an emulsion.

Rub the casein into the wood with a cloth. Two coats (wait one hour between coats) may be necessary depending on the consistancy of the casein (do not sand this sizing).

Before applying casein made with borax, you can rub balsamic vinegar into the wood with a cloth. Rub energetically and let it dry without sanding. Repeat the operation once. This closes the pores of the wood. Or you can use tea, chicory, coffee or whatever other coloring agent you wish.

Casein sizing suffices in itself and does not require filling the pores beforehand. However, if you don’t want to take any risks, you can fill the pores.

 

This sizing is one of the many possibilities for preparing the wood; it is not the universal recipe of the Italian violin makers.

 

www.kreitpatrick.com

[joerobson]

Hi Joe,

 

These are very interesting photos!  Thank you for posting them!!

As you mention, not every Strad is the same.  In fact the more I see the more I become aware of differences.  And then there is the effect that different lighting has.  The appearance of Strad varnish and ground certainly seems to change very significantly under different lighting and changes in light direction. 

 

On the topic of ground appearance, I wonder whether much of the change between instruments is merely due to how his ground system reacted with each piece of wood.  Having tried many and varied ground systems, it seems that wood difference is one of the major factors, if not the major factor, in not being able to get a consistent appearance from one instrument to the next.

 

I am not sure that I understand your sentence "Even on the samples where a particular protein was found, she would not classify the finding as intentional."  Could you please expland on this?

 

Many thanks.

 

John

 

John,

M. Brandmair is very precise about her findings...and not inclined to speculation.  She said that there was nothing in the data that would confirm that the presence of amino acids at or near the wood surface was an intentional application by the maker.

As we interpret this data for our own use and and understanding I think it is very important to be precise in our observation.  The optical properties of the classic ground create an internal sparkle in the wood that is beyond a surface polish or sheen.

Joe

[robertdo]

With very sensitive analytical methods you can find basically everything everywhere. But a sizing or a sealing with a protein (casein, albumin, hide glue etc..) would leave a "huge" amount of it, and would represent a distinct layer between wood and varnish, while contaminants present for example in the linseed oil (lots of proteins in linseed oil) could mean traces in the varnish. So the presence of amino acids (I didn't read the book, but people seem to say "amino acids" rather than protein) without any other information is rather vague. Even knowing the relative proportion of each amino acids could be of help.

[NewNewbie]

When JP Echard did his tests he set out to find, define, and quantify the "mineral ground" once and for all.  When his testing methods did not show this "layer" he assumed he made a mistake and did the analysis all over again...only to reach the same conclusion. 

on we go,

Joe

 

 

Seems to confirm what Michael Darnton was telling us right from the start.

Now I wonder how many times that has happened?

[NewNewbie]

With very sensitive analytical methods you can find basically everything everywhere. But a sizing or a sealing with a protein (casein, albumin, hide glue etc..) would leave a "huge" amount of it, and would represent a distinct layer between wood and varnish, while contaminants present for example in the linseed oil (lots of proteins in linseed oil) could mean traces in the varnish. So the presence of amino acids (I didn't read the book, but people seem to say "amino acids" rather than protein) without any other information is rather vague. Even knowing the relative proportion of each amino acids could be of help.

See John Harte's post #89 and he lists the proteins.

 

Wood also contains protein.

 

"Hi Joe,

 

Thank you for your reply and comments.

 

My notes taken while reading Brandmair's section in “Stradivari Varnish” mention the following:

1. Advanced analyses via indirect ELISA on microsample 1730/5 which contains wood confirmed a small amount of casein.

2. Re sample 1720/3, via ELISA found various proteins – tests for collagen as well as ovalbumin were positive in this sample. Further collagen tests considering fish and sturgeon were negative, etc..

3. Re Strad cello wood sample 1707, ELISA definitely positive for collagen (in general) and negative for all other tested proteins. Fish and sturgeon can also be excluded. GC/MS confirmed ELISA analysis.

4. Re old Italian cello 17??, probably Strad, indirect ELISA found two different proteins; i.e., ovalbumin and collagen. GC/MS confirmed collagen.

 

I must emphasize that these are my notes and will not reflect the exact wording that appears in the book. I can dig out the book and check (and it will take some digging in my workshop!) but I am positive that the mention of specific proteins will have resulted from what actually appears in the book.

 

My posting in response to Robertdo's post #84 was focused on Echard and his teams' findings relating to the presence or not of proteins. The controversy surrounding the presence or not of any mineral ground is a separate issue again.

 

I hope that this makes sense.

 

John"

 

Underlines are added by me.

[Oded Kishony]

Seems to confirm what Michael Darnton was telling us right from the start.

Now I wonder how many times that has happened?

 

Easier to list the times he was wrong, much shorter list :-)

 

Concerning the collagen mentioned above. If the sample was taken anywhere near any joint, the source could easily be from the glue. That's why it would be handy to know the (precise) location of the sample.

 

IIRC Sacconi also mentions seeing some minerals, is that right?

 

Oded 

[John Harte]

M. Brandmair is very precise about her findings...and not inclined to speculation.  She said that there was nothing in the data that would confirm that the presence of amino acids at or near the wood surface was an intentional application by the maker.

 

Hi Joe,

 

M. Brandmair was quite specific in identifying the area where there was a protein presence within each analysed sample considered in her section of the book.  This, in each case, was a reasonably well defined area which might suggest that this detected presence is less likely to be there as a consequence of some random event or residue from a previous repair.  If this protein presence was, for example, residue from a previous repair, there would likely be a much more general presence than apparently exists.  Furthermore, while an unintentional residue due to a repair might explain the presence of collagen, the presence of casein and particularly ovalbumin are more difficult to explain away.

 

In contrast to what M. Brandmair clearly states in her section of “Stradivari Varnish”, Echard and his team ruled out “protein materials such as egg, casein, or animal glue as significant components” in the same area of the samples that they analysed.

 

It would be interesting to know whether there are any known limitations regarding specific protein detection using indirect ELISA (Enzyme-linked immunosorbent-assay).  I haven't been able to find anything regarding this.

 

 

I remain mystified......

 

John

[JohnCockburn]

re: echard vs brandmair, is it not conceivable that Strad changed procedures from time to time?

[Patrick KREIT]

For those who believe that it is impossible to reproduce Italian style varnish, see Philippe Girardin’s page on varnish:

 

 

www.philippe-girardin.net/content.php?id=5〈=EN

[robertdo]

re: echard vs brandmair, is it not conceivable that Strad changed procedures from time to time?

It's not inconceivable indeed. It must be noted though that the instruments used during analysis in Echard et al paper were made on a 30 years period, and the conclusion was that the varnish composition was very similar and the arrangement (that is a layer of drying oil inside the wood followed by a resin/oil varnish) was identical. But of course it's only a handful of violins, and a larger sample could give a different picture. However if you consider that the Provigny, the Sarrasate, the Davidov are good examples of a Cremonese varnish/ground instruments then you have to conclude that this way of doing is at least a good way.

[Peter K-G]

For those who believe that it is impossible to reproduce Italian style varnish, see Philippe Girardin’s page on varnish:

 

 

www.philippe-girardin.net/content.php?id=5〈=EN

Thanks Patrick,

I'm studying varnishing at the moment and at this point I'm not changing from my formula with Oldwood. I had plans to try something else but why change something that works! Violin #5 is the first violin I'm happy with the varnishing result.

I got it a little bit too dark but this is good for me:

Lot of information in this topic

[Peter K-G]

(and yes I'm going to paint the f-hole walls black but I will wait to see how A0 develops for some months)

[John Harte]

re: echard vs brandmair, is it not conceivable that Strad changed procedures from time to time?

 

It appears that Echard and his team used the results of synchrotron radiation micro-FTIR spectroscopy (SR–FTIR) to form their view that egg, casein and animal glue were not significant components. They mention no exceptions to this finding anywhere within their 2009 communication “The Nature of the Extraordinary Finish of Stradivari's Instruments”. (Incidentally, there does seem to be some noise in their included spectra in the region where amide I and amide II bands would appear and, as such, could it be conceivable that there might be possible masking of any protein presence? Is there anyone here familiar with interpreting SR-FTIR spectra? )

 

M. Brandmair found a specific protein presence in all 4 Strad and possible Strad samples that she was able to test for such using indirect ELISA. Histochemical staining reactions (fuchsin S 1%), where used, also proved positive without exception (Strad, N.Amati and del Gesu samples).

 

Re Echard vs Brandmair, it seems to me that there may be issues more related to interpretation of analytical data and possible limitations associated with various analytical techniques than Strad changing his procedures from time to time.

Note here that I am not saying that Strad didn't change his procedures. He may well have. The varied presence of collagen, casein and ovalbumin found by M. Brandmair could suggest a variation in procedure. 

[NewNewbie]

It would be interesting if samples containing known coatings were given to both research teams, and see how they fair.

I think that a sample with a protein base coat would be spotted right away by them, and so Echard finds none, and Brandmair

finds some, but not enough to say a coating.  They seem to be more in agreement to me than not.

 

If the research tools used lacked the ability to determine a protein coating, then the researchers would have chosen one that could, since the use of protein coatings is quite prevalent in artwork.

 

Condax found only 7% protein IIRC, and so once again not what one would expect from a full coating.

So I am wondering if we are seeing a slight change in procedures.

 

Where's Bruce Tai these days???????

[joerobson]

Hi Joe,

 

M. Brandmair was quite specific in identifying the area where there was a protein presence within each analysed sample considered in her section of the book.  This, in each case, was a reasonably well defined area which might suggest that this detected presence is less likely to be there as a consequence of some random event or residue from a previous repair.  If this protein presence was, for example, residue from a previous repair, there would likely be a much more general presence than apparently exists.  Furthermore, while an unintentional residue due to a repair might explain the presence of collagen, the presence of casein and particularly ovalbumin are more difficult to explain away.

 

In contrast to what M. Brandmair clearly states in her section of “Stradivari Varnish”, Echard and his team ruled out “protein materials such as egg, casein, or animal glue as significant components” in the same area of the samples that they analysed.

 

It would be interesting to know whether there are any known limitations regarding specific protein detection using indirect ELISA (Enzyme-linked immunosorbent-assay).  I haven't been able to find anything regarding this.

 

 

I remain mystified......

 

John

 

John,

First off, your familiarity with the testing methods is stronger than mine.  However I have discussed these methods with several folks who are very familiar....and also are violin makers of good repute. The collective conclusion seem to be that given the testing methods it would be impossible to NOT find this variety of proteins at that level in the varnish as the violins were made by human hands.  Also, when I asked M. Brandmair directly about this she was quick to repeat that one cannot conclude an intentional act by the maker based on the data.  This does not exclude the possibility that some sort of protein based sealer was used, but it greatly reduces the probability. 

 

More to the point as far as I am concerned:  I believe what I see.  The optical effect of a protein based application, sufficient to act as a sealer on the wood surface, would be to reflect light back to the eye from that surface.  The optical effect of the classic ground is to allow the light to penetrate the surface and then bounce around before exiting.

I too do not deny the possibility of a protein based sealer which could allow this to happen.  However seeing is still believing and I have yet to see such material in use that comes even close to such an effect.  I do remain open to the possibility.....

on we go,

Joe

[Patrick KREIT]

Roberto

 

Echard is not a violin maker. "Cobbler, stick to thy last!" **   You must always check things out for yourself. If you apply a coat of pure linseed oil directly on the white wood of your violin, I guarantee you'll have to throw it away. Ask Don Noon: he learned this the hard way!

 

**  http://en.wikipedia.org/wiki/Sutor,_ne_ultra_crepidam

 

www.kreitpatrick.com

[robertdo]

I don't think linseed oil deadens the sound as much as it is sometimes said. At least if you apply small amount of sunthickened oil. Also it's a little bit strange to say that linseed oil is not good and at the same time find several instruments for which the first few layers of cell walls are filled with it. I mean I never heard the Provigny, the Davidov or any of the other studied by Echard, but linseed oil was there, no doubt.

[Don Noon]

If you apply a coat of pure linseed oil directly on the white wood of your violin, I guarantee you'll have to throw it away. Ask Don Noon: he learned this the hard way!

Actually, I did it the easier way... testing on samples first, and found results that I thought would be bad acoustically. Additionally, Sam Z. told me he never uses oil-bearing stuff in the first coat or so. That was sufficient for me... I never put oil on bare wood of a violin.

[Janito]

It would be interesting to know whether there are any known limitations regarding specific protein detection using indirect ELISA (Enzyme-linked immunosorbent-assay).  I haven't been able to find anything regarding this.

 

I know a fair bit about this - let's just say that the data are completely dependent on the antibodies used and that the latter have the propensity to misbehave without apparent reason.

 

Recently we had samples measured for a protein by a major commercial lab using a fully validated assay.  The assay was then reconfigured and fully validated again.  Unfortunately, when the same samples were measured with the new assay, the results were different, even though the assay had gone through stringent 'validation' to quantify specificity and standard curves were generated using the same calibrators.

 

Ps - My "Lunch" comment was not completely frivolous.

[Janito]

I know a fair bit about this - let's just say that the data are completely dependent on the antibodies used and that the latter have the propensity to misbehave without apparent reason.

 

Recently we had samples measured for a protein by a major commercial lab using a fully validated assay.  The assay was then reconfigured and fully validated again.  Unfortunately, when the same samples were measured with the new assay, the results were different, even though the assay had gone through stringent 'validation' to quantify specificity and standard curves were generated using the same calibrators.

 

Ps - My "Lunch" comment was not completely frivolous.

 

 

 

pps - variability could simply reflect AS washing his hands or not.

[John Harte]

pps - variability could simply reflect AS washing his hands or not.

 

And having eaten omelette for lunch!

 

Janito, thank you very much for your post #120 in this thread.

Your comments are very interesting and help clear up one of the concerns that I have had.

 

I much appreciate your willingness to be involved in this discussion.

 

John

[John Harte]

John,

First off, your familiarity with the testing methods is stronger than mine.  However I have discussed these methods with several folks who are very familiar....and also are violin makers of good repute. The collective conclusion seem to be that given the testing methods it would be impossible to NOT find this variety of proteins at that level in the varnish as the violins were made by human hands.  Also, when I asked M. Brandmair directly about this she was quick to repeat that one cannot conclude an intentional act by the maker based on the data.  This does not exclude the possibility that some sort of protein based sealer was used, but it greatly reduces the probability. 

 

More to the point as far as I am concerned:  I believe what I see.  The optical effect of a protein based application, sufficient to act as a sealer on the wood surface, would be to reflect light back to the eye from that surface.  The optical effect of the classic ground is to allow the light to penetrate the surface and then bounce around before exiting.

I too do not deny the possibility of a protein based sealer which could allow this to happen.  However seeing is still believing and I have yet to see such material in use that comes even close to such an effect.  I do remain open to the possibility.....

on we go,

Joe

 

Hi Joe,

 

Thank you for your reply.

 

What you mention in your first paragraph makes a lot of sense.  (Although I am not sure that I would be prepared to say much regarding probability when it comes to this issue!)

 

I also agree in a general sense regarding the optical effects of protein applications. However, as we know, there are many ways in which proteins can be used or incorporated into various applications, some of which can quite successfully allow light to penetrate the surface and then bounce around before exiting.

 

Attached are several more photos taken through illuminated 15x magnifiers. Two show again the casein glue and oil varnish emulsion on spruce (one taken under incandescent light and the other under LED light). The other two show spruce detail on two different Strads (taken under incandescent light). All of these photos were taken within the last two weeks using the same camera. The same magnifier with incandescent bulb was used in taking three of the photos. These photos are very limited in what they show but hopefully they will at least partially illustrate my above point, especially when compared to the photo showing a thin casein glue size on spruce in post #63.

 

John

[NewNewbie]

 

Roberto

 

Echard is not a violin maker. "Cobbler, stick to thy last!" **   You must always check things out for yourself. If you apply a coat of pure linseed oil directly on the white wood of your violin, I guarantee you'll have to throw it away. Ask Don Noon: he learned this the hard way!

 

**  http://en.wikipedia.org/wiki/Sutor,_ne_ultra_crepidam

 

www.kreitpatrick.com

 

That Echard is not a violin maker is for me a plus, as he does not carry any preconceived notions that may hinder his work.

[Peter White]

Hi folks:  Thank you all for the wide variety of responses to my original question about the conclusions of Stradivari Varnish.  No doubt the book is full of information, and many of us read the book and come away with different interpretations of what the authors are saying.  It is true that they are very guarded in the way they qualify almost every statement, and they leave plenty of room for various interpretations.  However, the first part of the book outlines a method of varnishing that involves four well-written sections: Impregnation, staining, clear coat and final color coat.

Let me ask the question another way: Does it make sense to you violin makers that Stradivari (and others) could have worked in this 4 step, relatively simple (to him), probably traditional, efficient method of finishing his instruments?

To Patrick:  thank you; I will try your methods.

To the person who asked about the resin: I don't have the book with me because I am on vacation, but as I remember the authors called the resin a pine, simple gum resin easily obtainable.

By the way, when I saw the Messiah at Oxford, the varnish looked very thin and very hard.  It did not look like the Strad's in the museum in Cremona or in the various shops where I have looked long and hard at Strad instruments. I believe this is because centuries of polishing and use have changed the look of the Strad's we normally see in shops or exhibits.

In my mind it could be that the Messiah is an example of the four step method with a lean varnish. It is examined in Stradivari Varnish.

Just a general observation: I personally doubt many contemporary makers varnish new looking violins in four steps. 

Thanks for your interest, Peter