Michael_Molnar

Any Cremonese Basis for Colored Rosinates?

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Michelman pp 31-43 argues for a historical basis to rosinates extending back to Cremonese times. I think his arguments are weak. 

I have also looked for modern analyses that could resolve this issue and found none. Maybe I overlooked someone's research. Does anyone have a better argument for rosinates used by Cremonese makers of Stradivari's time?

 

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I am similarly unconvinced. The recipes are a little fussy, even with today's lab grade reagents. I like certain things about rosinate varnishes, but so far I have not encountered any research that makes a convincing enough argument for it's historical authenticity.

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curious to know what is a rosinate  as being mentioned here.  I think the simplest varnish  one could make is based on metal resinates (rosinates?). 

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I read somewhere recently that research had contraindicated Michelman type metallic rosinates.

It was either in Tai's survey of researches, or perhaps in Brandmair.

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19 minutes ago, FredN said:

curious to know what is a rosinate  as being mentioned here.  I think the simplest varnish  one could make is based on metal resinates (rosinates?). 

I think a simpler and more historical varnish would be one made of just two, naturally occurring ingredients: resin and oil.

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An article "The Real Thing" by John Dilworth that appeared in the October 1984 Strad magazine details analyses of several old Italian violin and cello varnish samples carried out by Raymond White.  Quoting from this, "White was quite firm in ruling out both Michaelman and Fulton theories in three particular examples.  The metal soap rosinates of Michaelman varnish are apparently very distinctive and would have been easily revealed by these analyses."

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9 hours ago, Michael_Molnar said:

Michelman pp 31-43 argues for a historical basis to rosinates extending back to Cremonese times. I think his arguments are weak. 

I have also looked for modern analyses that could resolve this issue and found none. Maybe I overlooked someone's research. Does anyone have a better argument for rosinates used by Cremonese makers of Stradivari's time?

 

I think michelmans theory originated from the discovery of metal components in the varnish. It seems that at his time it that this was the best explanation for metal salts in the varnish. But from there no more supporting evidence came out. 

In the end I find chemical analysis always difficult to understand and in those terms I don't care too much if my approach is, seen by a scientist, authentic. However, I do care about optical proportions just comparing my varnish results to originals in different lightening conditions.

With those framing parameters I still like to use the michelman  approach because I can make quite easily my own colors for the optical results I want to have. And I am saying approach because I am not using the precise original recipe any more.

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5 hours ago, Andreas Preuss said:

I think michelmans theory originated from the discovery of metal components in the varnish. It seems that at his time it that this was the best explanation for metal salts in the varnish. But from there no more supporting evidence came out. 

I feel that he confuses making lakes with making rosinates. He refers to old ingredient lists from making varnish and lakes, and uses the mention of potash as evidence for rosinates. However, potash is used in making lakes. Rosinates may give beautiful results but they are modern inventions. 

I agree that there is no historical evidence for a Cremonese rosinate. 

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12 hours ago, John Harte said:

An article "The Real Thing" by John Dilworth that appeared in the October 1984 Strad magazine details analyses of several old Italian violin and cello varnish samples carried out by Raymond White.  Quoting from this, "White was quite firm in ruling out both Michaelman and Fulton theories in three particular examples.  The metal soap rosinates of Michaelman varnish are apparently very distinctive and would have been easily revealed by these analyses."

Badda bing. Badda boom.:lol:

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Michelman gives several different recipes for the same rosinate, with varying concentrations of alizarin... with the higher concentrations becoming insoluble in turpentine.  It is not clear to me if there is a sharp dividing line between a rosinate and a lake, or if you can have a continuum of results with diminishing rosin content (I have to think it's the latter).  How would you distinguish a lake ground into varnish from a highly colored rosinate ground into varnish?

Personally, I think lakes are annoyingly hard to grind and more intensely colored than I need, and throwing a little rosin into the lake-making process would give something easier to deal with.  What you call it or how you detect it, I don't know.

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4 hours ago, Don Noon said:

How would you distinguish a lake ground into varnish from a highly colored rosinate ground into varnish?

1

I think your answer lies here:

19 hours ago, John Harte said:

An article "The Real Thing" by John Dilworth that appeared in the October 1984 Strad magazine details analyses of several old Italian violin and cello varnish samples carried out by Raymond White.  Quoting from this, "White was quite firm in ruling out both Michaelman and Fulton theories in three particular examples.  The metal soap rosinates of Michaelman varnish are apparently very distinctive and would have been easily revealed by these analyses."

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However, I do not know how White would have made this distinctive determination. If I had the time to read his old papers, I would pursue this. However, White was a pretty good scientist and I will take Dilworth's statement as being sufficient. 

I use pigments in Layer 4 just like Strad et al. I find that pigment concentrations need not be high in a varnish that uses cooked (reddish) rosin. I also like the ability to adjust the chroma using color complements. Well, that floats my boat. ^_^ 

Rosinates, nevertheless, are beautiful and easy to use. 

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