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Archiver

Stradivari Betts violin

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I thought it may be what Mr. Molnar said too until I went to scrape a belly a little bit ago.  I had to wait to comment because I wet the wood earlier to raise grain.  I scraped along the outer long arch and I can see the same lines as the Betts photo.  Maybe just coincidence?

 

As soon as belly is fully prepared inside and out I'll give another opinion, for the time being it's the scraper action bringing out the pattern {my opinion}.    

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It's an artifact of how the scanning works. The lines being discussed are essentially elevation contours for the arches of the plate.

 

Think about it this way. The CT scanner is taking scans of the violin along well defined directions and positions and then piecing them together to form an image of the entire violin. There are bound to be small artifacts at the places where the data gets stitched together.

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It is.

 

The strength of the effect will depend on the CT scanner used, its software, scan parameters... but these lines are visible in scans of other violins.

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I'm surprised by reading your answers ..

Yes, me too.

 

It's clearly one of these...

 

post-35343-0-62001500-1459298194_thumb.jpg

 

If you place a polished silver cylinder in the middle of the "Betts" top plate, you will be able to read a chapter of Torquato Tasso...  :ph34r:

 

post-35343-0-95268000-1459298520_thumb.jpg

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Micro alien crop circles.

April doesn't start for a few more days... :rolleyes:

The real explanation is that Strad only had large diameter cutters for his CNC. Not as big as Sacconi's, though. :lol:

post-35343-0-07730800-1459306066_thumb.jpg

Not nearly as embarrassing as the Bros. Amati painted flames on the maple...

post-35343-0-53695800-1459306147_thumb.jpg

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April doesn't start for a few more days... :rolleyes:

The real explanation is that Strad only had large diameter cutters for his CNC. Not as big as Sacconi's, though. :lol:

attachicon.gifimage.jpg

Not nearly as embarrassing as the Bros. Amati painted flames on the maple...

 

 

I wonder the issue of graduation thick for such frequency variable, assuming that the center area is thinnest. What are the mathematical value for the individual layers? Is it possible to perform that so many graduation on such a thin front plate?

 

 

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Very nice pictures :)

We want more :))

 

 

 

I wonder the issue of graduation thick for such frequency variable, assuming that the center area is thinnest. What are the mathematical value for the individual layers? Is it possible to perform that so many graduation on such a thin front plate?

 

Why the changes in voice and font? Pardon me, but it seems somebody gave to you this quote as it were, and you are not paying attention to the explanations given above. No offense intended, but I find this very peculiar.  :unsure:

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It is easy to think about Archiver's "is it possible to perform many grads on a front plate" but it is hard to explain here so that my reply would be understandable.  And it is not decided yet if the contours on paper are machine made or is that actually wood being viewed.  I have a half template that I use to mark out long arch height/depth locations.  A highest point in front of bridge may be 15.8mm but 4 inches towards the lower bout may be at 13.3mm for example.  A maker knows to reach the 13.3mm mark he/she will have to remove wood from the 15.8mm area.  On the way down the layers are exposed assuming it is the wood causing the effect.  It still could be machine made contours that show up.  They do look interesting and I do wonder now how much more of an exact copy of plans could be made by converting those to paper.       

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What are these lines visible on the CT scan of the front of the original Stradivari Betts violin? 

 

(I mean these lines, which are randomly marked in red)

 

Did you evidence the lines in red?

 

You can look on them as iso-heights or lines of equal height as can be seen on a topographic map of some mountainous or hilly terrain. The CAT scanner is reading "slices" on the coronal or frontal plane. This is the plane of the lower edge of the belly where it touches the ribs. These slices are taken at incremental distances from this plane (usually about 0.5 to 0.75 mm) and, when combined in the computer, give us an image of the belly as if it were translucent. In areas of overlap between the slices the computer algorithm leaves a ghost which shows the arching progression like the diagram Addie posted earlier from the Sacconi book.

 

Bruce

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Why the changes in voice and font? Pardon me, but it seems somebody gave to you this quote as it were, and you are not paying attention to the explanations given above. No offense intended, but I find this very peculiar.  :unsure:

 

because I use a translator, after translating the text paste it into notebook, word processor in a notebook has default font, which is smaller that I change font on this, which usually I use and increases letters (Helvetica size 13), later paste that changed text to the post. Once the font has not changed. English is not my primary language. that's all

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Did you evidence the lines in red?

 

You can look on them as iso-heights or lines of equal height as can be seen on a topographic map of some mountainous or hilly terrain. The CAT scanner is reading "slices" on the coronal or frontal plane. This is the plane of the lower edge of the belly where it touches the ribs. These slices are taken at incremental distances from this plane (usually about 0.5 to 0.75 mm) and, when combined in the computer, give us an image of the belly as if it were translucent. In areas of overlap between the slices the computer algorithm leaves a ghost which shows the arching progression like the diagram Addie posted earlier from the Sacconi book.

 

Bruce

 

These lines are interesting for me because I discovered a layer of the ground varnish, which is formed just in the same way as the lines on the CTscan.

These lines are visible as a layers on the outside, especially under the fingerboard. They are very perfectly spaced apart, transparent and very interesting.

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