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Strad (and other) models database?

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On 10/3/2016 at 4:13 AM, Stavanger said:

I figured I'll start making a viola using the 1672 "Forma Viola Contralto" shape from the great resources provided here: http://www.thestradsound.com/maestronet/stradivari-forma-by-addie

However, does anyone have some high-res photos, a poster, maybe scroll and archings etc. for violas made with this form they would like to share with me? 
In advance, thank you.
 

Stav, if someone who has participated in and/or followed this thread can identify any instruments known to have been made on this forma or one close to it, I'll be glad to look through my archives and see if I have anything that would be of use to you.

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Probably not that urgent, Addie - I don't think many workshops had to stop production - but your attention to detail really is remarkable.  I have to admit that somehow I missed this whole amazing archive of drawings you made until today.   It is a serious contribution.  Thank you. 

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1 hour ago, JacksonMaberry said:

I printed all of Addie's strad form documents and compared them with the Titian CT scan on a light table. The one that fits most closely (by quite a bit) appears to be the PM. 

What is the PM form?:)

From my observations the Titian corresponds very well to the P 1705 form, despite the scan is poorly defined.

An even better match of this form is with the Gibson/Huberman, the ribs scan on the poster is also much better as definition.

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5 minutes ago, Davide Sora said:
 

What is the PM form?:)

 

From my observations the Titian corresponds very well to the P 1705 form, despite the scan is poorly defined.

 
An even better match of this form is with the Gibson/Huberman, the ribs scan on the poster is also much better as definition.

PM MS1062, which I understand is not listed in Sacconi's work and is possibly not from Antonio's hand. I was struck by how well it fit. 

I think I read here on Maestronet that the P 1705 is the correct form for the Titian, and so it's the first one I tried, but it seemed too long and I couldn't get everything to line up well. I trust you more than I trust myself, however, and I will check it again tomorrow. It is a shame that the CAT scan resolution is not so clear. =(

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16 hours ago, JacksonMaberry said:

PM MS1062, which I understand is not listed in Sacconi's work and is possibly not from Antonio's hand. I was struck by how well it fit. 

I think I read here on Maestronet that the P 1705 is the correct form for the Titian, and so it's the first one I tried, but it seemed too long and I couldn't get everything to line up well. I trust you more than I trust myself, however, and I will check it again tomorrow. It is a shame that the CAT scan resolution is not so clear. =(

Ok, now I get it.

PM form is an interesting one, not quite dissimilar from P forms, the provenance from Cozio di Salabue collection may put it in the Stradivari workshop.

But the widths measures seems too wide in the C bouts and too narrow in upper and lower bouts for a good match with Titian measures, but deformation and displacement after the ribs are separated from the form may play a role, so who really knows....

My daring guess is that it could be a Guadagnini copy of the P form made at the time when he was working for Cozio, based on the unusual thickness of this form (15,5 mm) that may pose some problem for gluing linings on both side with the ribs still on the form as Stradivari did and that Guadagnini did not, looking at the huge difference in his top and back measures on the same violin.

Just my very hypothetical and rather uncertain opinion.:unsure:

PS The photos on the MdV catalogue are taken probably with a short focal lenght lens (look at the holes in the forms) and this may lead to some distortion in the outline.

The measures of the PM form isn't very clear how they was taken (not specified) and although the widths can be trusted it is not clear how the length has been taken,

even if I suppose at the tips of upper and lower blocks as Pollens did.

59c3e06ca8376_P1705DenissuPMms1062.thumb.jpg.8a4ce6019fb7bf5a2eb02e424c84da63.jpg

 

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Your insights are most appreciated, Davide! 

I did check them all again today and I agree you are right - the P 1705 is a better match. I think I breathed in too much Paulownia dust yesterday, it was affecting my perception! 

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Not disagreeing with Davide's interesting observations.

 

Remember when trying to match forms to violins, it's not a straight shot.    If you accept Hargrave's premise that the rib structure was pegged to the board for the plate and then twisted around a bit for alignment, then you can't expect direct correspondence between form outline and violin outline.

I use this method in my own making.  It certainly works well, regardless if it's what the old guys did.   And my bet is that they did make this way.   Otherwise, it is hard to understand the very frequent difference in corner levels from bass to treble side in classical work.   No one makes a mold with these differences.  But they arise naturally when you use this method of twisting the rib structure on the plate pegs.

The rib structure is very flexible.   You can pin it to the board for the back plate at a length either longer or shorter than your form.  You can also set the upper, center, and lower bout widths to somewhat different ratio choices than you used in making a form.  So there is no reason to expect direct correspondence between forms and instruments.

 

 

 

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I draw my outlines very carefully and cut the mold as close as I can and then bend the ribs as close as I can and put the whole thing altogether and it isn't close  anymore to my starting drawing.

This sets up an internal personality conflict between between being a  "let it rip" vs. control freak. 

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7 hours ago, David Beard said:

Remember when trying to match forms to violins, it's not a straight shot.    If you accept Hargrave's premise that the rib structure was pegged to the board for the plate and then twisted around a bit for alignment, then you can't expect direct correspondence between form outline and violin outline.

I use this method in my own making.  It certainly works well, regardless if it's what the old guys did.   And my bet is that they did make this way.   Otherwise, it is hard to understand the very frequent difference in corner levels from bass to treble side in classical work.   No one makes a mold with these differences.  But they arise naturally when you use this method of twisting the rib structure on the plate pegs.

The rib structure is very flexible.   You can pin it to the board for the back plate at a length either longer or shorter than your form.  You can also set the upper, center, and lower bout widths to somewhat different ratio choices than you used in making a form.  So there is no reason to expect direct correspondence between forms and instruments.

6 hours ago, Marty Kasprzyk said:

I draw my outlines very carefully and cut the mold as close as I can and then bend the ribs as close as I can and put the whole thing altogether and it isn't close  anymore to my starting drawing.

This sets up an internal personality conflict between between being a  "let it rip" vs. control freak. 

I agree, perfect matching is not possible for many reasons , that's why attribution is always uncertain and debatable.

This is particularly evident to those who test the construction systems on his skin.

However sometimes there is a surprising match, because it was not always necessary to make corrections that change the ribs outline (i.e. I think that the neck was nailed straight at the first shot most of the times, with no need for further big correction), but look for millimetric accuracy is meaningless.

It is more a matter of interpreting the correspondence of the lines and how they could be changed from those of the form, surely not an exact science....:)

Here is a better match of PM form to P/B form (thanks to Francois Denis for sharing his scans of both side of original forms), even the thickness is similar with PM at 15.5 mm and P/B at 15.0 mm, the only one so thick among Strad's forms.

With the P1705 remake he was tired of having problems with linings, so he made it thick just 13 mm;)B)

59c4e28ea1388_PbDenissuPM-MS1062.thumb.jpg.d08082816b323ba8569de692b7de4984.jpg

 

 

 

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I remind you that it is possible to download the outlines (recto verso)  of the Stadivari forms on the website of the traité de lutherie

discrepancies of the scans are less than 0.5mm in the lenght almost nothing in the width

www.traitedelutherie.com

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12 hours ago, David Beard said:

Not disagreeing with Davide's interesting observations.

 

Remember when trying to match forms to violins, it's not a straight shot.    If you accept Hargrave's premise that the rib structure was pegged to the board for the plate and then twisted around a bit for alignment, then you can't expect direct correspondence between form outline and violin outline.

I use this method in my own making.  It certainly works well, regardless if it's what the old guys did.   And my bet is that they did make this way.   Otherwise, it is hard to understand the very frequent difference in corner levels from bass to treble side in classical work.   No one makes a mold with these differences.  But they arise naturally when you use this method of twisting the rib structure on the plate pegs.

The rib structure is very flexible.   You can pin it to the board for the back plate at a length either longer or shorter than your form.  You can also set the upper, center, and lower bout widths to somewhat different ratio choices than you used in making a form.  So there is no reason to expect direct correspondence between forms and instruments.

 

 

 

A compelling take, for certain. As always, thank you.

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4 hours ago, francoisdenis said:

I remind you that it is possible to download the outlines (recto verso)  of the Stadivari forms on the website of the traité de lutherie

discrepancies of the scans are less than 0.5mm in the lenght almost nothing in the width

www.traitedelutherie.com

 

That's what I did, thank you for making them available.

I have then converted the Pdf into Jpeg with the computer "stamp" button to be able to use them for overlays.
I find the overlapping of the two sides of the form particularly useful for this kind of matching (form to form or form to violin).

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1 hour ago, Nick Allen said:

How much distortion are we going to see when trying to superimpose a photograph on top of essentially what is a blueprint? 

Photographs are extremely hard to produce with no distortion. long lens is first step, but optical distortions always creep in.

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CT scans for violin and the use of a scanner for flat objects like forms is the only way to avoid distorsion, but it is not always easy to have them available.

Probably a high quality 200mm focal length lens designed to minimize optical distortion and a very careful shot taking care of the parallelism between the object and the camera sensor can guarantee good accuracy with small objects such as violin bodies, very good for scroll.
Less than 100 mm focal lenght lens is inadequate.

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Is it possible that some of the original molds has lost some millimeters?

For examble mold Pb, what would be the point of making center line, if its not center at all. If you draw a violin model, you dont make 2mm differences by mistake.

I would put 2mm more to the lower bouts left side if you look from the side the writings are. So the total would be 198mm.

In Addies drawings, the left side looks beaten up.

 

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1 hour ago, Kimmo89 said:

Is it possible that some of the original molds has lost some millimeters?

For examble mold Pb, what would be the point of making center line, if its not center at all. If you draw a violin model, you dont make 2mm differences by mistake.

I would put 2mm more to the lower bouts left side if you look from the side the writings are. So the total would be 198mm.

In Addies drawings, the left side looks beaten up.

 

By the looks of Francois' red drawings, I would deem some of these forms un-usable, personally. Like near the C bout corner blocks. Just two completely different profiles from one side to the other.

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8 hours ago, Nick Allen said:

How much distortion are we going to see when trying to superimpose a photograph on top of essentially what is a blueprint? 

 

This is one of the major differences between modern making and the old methods: there is no blueprint or predetermined complete design.

From my research into the geometry and methods of the old making (primarily Cremona), everything is by simple geometry constructions with dividers and straight edge and simple integer proportions.    But the design plan is more like a recipe than a blueprint, and there is every indication that the 'recipe' was adjusted ad hoc as building proceeded.

So you make a mold controlling the geometry construction by selecting ratios between various parts.   Perhaps you set the width of the lower bout as 4/7 the body length, and maybe you set the upper line for the lower corners at 2/5 body.     But after you bend ribs onto the mold and remove the rib structure, you are free to make different choices in the outline of the back.  You can push the rib structure around to fit your new outline choices for the back.   Particularly you have freedom with the major bout widths and the body length.   But once you set these, and perhaps push the corner level around a little, you won't have much control left regarding the curve shape of the center bout.   On the mold, you would have almost certainly have used either the upper or the lower bout width to give you the diameter of the large circle for the center bout shape.    But now that you're working the outline for the back, you may need to make a different choice for the large circle in order to follow your actual rib shape through the center bout.  

This is just one example of the many situations were it appears the old makers likely made their actual choice of geometry and/or ratios for sizing once they got to a certain stage of work, and not ahead of time.

The idea of fully working out every design detail ahead of building is modern.  And a major difference with classical making.

 

 

 

 

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On 2/3/2016 at 1:51 PM, Addie said:

Thanks.  People who have money to spend are recommended to buy the works of Sacconi, Pollens, and Denis to study up on Stradivari's tools, methods, and patterns.  Also this book http://www.museodelviolino.org/nuovo-libro-antonio-stradivari-disegni-modelli-forme/

which is not out yet, shows great promise... including new photos of the Stradivari Collection on disk.

 

As a side line (shameless plug), I do make instrument labels for people.  ;)

 

Here's a free sample, that anyone may use. :lol:  Print out the PDF to see the NO-PIXEL artwork.

post-35343-0-09543100-1454525451_thumb.jpg

Dutzend Label.pdf

So glad I stumbled upon these! I'm totally going to use them!  :D

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On 3/18/2016 at 4:34 PM, Addie said:

The Kreisler Guarneri del Gesù.  Inner rib outline taken from the CT Scan near the back.  Sound holes from LoC image with dimensions.  Outer edge of lines = edge. CM scale included.  Note asymmetry of treble sound hole eyes. 

 

 

post-35343-0-44556200-1458333204_thumb.jpg

Kreisler Form A3.pdf

Kreisler Form Tabloid.pdf

Kreisler Form Letter-1.pdf

Kreisler Form Letter-2.pdf

Kreisler Form A4-1.pdf

Kreisler Form A4-2.pdf

Hi Addie. We appreciate your wonderful work. Your kreisler del gesu is very close to the strad and biddulf plans except the shape of the top and bottom. They are a bit short. The strad poster and biddulf agree. 

20180505_183335.jpg

20180505_183223.jpg

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Hi, I did two types of drawings of forms: from existing forms, and from ct scans of instruments.  The Kreiser is taken from a ct scan showing the ribs just above the back.  I'm not a medical imaging specialist, so I can't account for the discrepancy.  There is cm scale in the drawing to help avoid printing errors.

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12 minutes ago, Addie said:

Hi, I did two types of drawings of forms: from existing forms, and from ct scans of instruments.  The Kreiser is taken from a ct scan showing the ribs just above the back.  I'm not a medical imaging specialist, so I can't account for the discrepancy.  There is cm scale in the drawing to help avoid printing errors.

It's difficult to get these PDFs to print at just the right scale. I take them to FedEx to get them printed on their big poster printers. It seems that these industrial printers are set to print slightly over sized, to cover up any edge artifacts or something. It's Like they print at 102.5 %, or something. So I have to scan the printouts several times at different combinations to arrive at just the right size. 

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