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Melvin Goldsmith

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1 hour ago, MikeC said:

With all the analysis that has been done by Echard,  Brandmair Greiner etc.  If gold was there we would know it by now. 

But it's still might look good on a new instrument to have something sparkly under the varnish.  

Correct, but Brandmair was not error free, IIRC she wrote that the stradivarian purfling contains iron, but it's not ferrogallic ink. But most recent analyses, confirmed that it was ferrogallic ink, I'm using it since 2012 and it works.

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20 minutes ago, Claudio Rampini said:

Correct, but Brandmair was not error free, IIRC she wrote that the stradivarian purfling contains iron, but it's not ferrogallic ink. But most recent analyses, confirmed that it was ferrogallic ink, I'm using it since 2012 and it works.

Yes, but he had found the iron. XRF analyses do not make mistakes, but only provide the elements they find. The interpretations of researchers based on the elements found may not be correct and do not provide any certainty.
In short, if there were some gold, they would have found it.

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1 hour ago, ctanzio said:

Since saffron was mentioned here is a link to a short discussion from this forum: (link)

TLDR: It can give a glow that varies from orange gold to brilliant yellow. Light fastness is a major issue. Use one of the modern dyes to achieve the same effect.

Thanks for digging that out.

 

The chemistry is interesting. Fresh saffron is more intensely coloured than aged.  The initial plant source of colourant is zeaxanthin which is insoluble in water but that degrades upon drying to highly colourful crocin which in turn transforms over time into more fragrant safranal.  Tannin might be a suitable mordant for a water or water+alcoholic solution of it. 

Safranal is found in a lot of other plants eg in fig leaves, tea, elderberry. 

 

I wonder if saffron, or tea from China would have been more valuable in the times of the Amati?

 

 

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Just now, Davide Sora said:

Yes, but he had found the iron. XRF analyses do not make mistakes, but only provide the elements they find. The interpretations of researchers based on the elements found may not be correct and do not provide any certainty.
In short, if there were some gold, they would have found it.

Correct, it's our artistic experience that can give results, the researchers don't. Sometimes the violinmakers justify their poor results with the researchers interpretations. I'm trusting more the ingenuity of the "gold rush" because it's important to have a sort of spiritual, symbolic image, hoping that someone will find his gold in the wood, not in the mines.

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A question for Claudio and Davide.   

There is a lutier in Cremona Lucas Fabro and he mentioned a coloring material,  he called it organetto.  But he didn't know the English name of it.  Have either of you heard of this material?  

I looked it up on google and the only thing I can find is some kind of small musical insturment. 

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1 hour ago, MikeC said:

A question for Claudio and Davide.   

There is a lutier in Cremona Lucas Fabro and he mentioned a coloring material,  he called it organetto.  But he didn't know the English name of it.  Have either of you heard of this material?  

I looked it up on google and the only thing I can find is some kind of small musical insturment. 

I am not sure, but it could be Alkanna Tinctoria (Alkanet in English) which is also called Orcanette or Orchanet:

https://en.wikipedia.org/wiki/Alkanna_tinctoria

If he was referring to an oil-soluble dye, that should be it.

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3 hours ago, Davide Sora said:

I am not sure, but it could be Alkanna Tinctoria (Alkanet in English) which is also called Orcanette or Orchanet:

https://en.wikipedia.org/wiki/Alkanna_tinctoria

If he was referring to an oil-soluble dye, that should be it.

I bought the Alkanna/Orcanetto in Florence, but I found it in the Morassi's workshop too. IIRC it works with spirit and oil varnishes, I didn't like it because the not so transparent hellish deep purple violet color, but it has good lightproof. For oil varnishes, you have to boil it in the linseed oil, but I don't think that it was used in the old cremonese varnishes, so I like solid pigments like the iron oxides and the natural madder lake.

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An interesting snippet about saffron

 

"A simple test is to be here yet reveal:

With a bit of sodium carbonate (Na2CO3) you can quickly and easily test the authenticity of saffron. Moisten the tips of the thumb and forefinger, dip your fingertips in the soda ash and grate now something of offered saffron between your fingers. be coloring your fingers deep yellow is all right."

 

 

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