Guarneri del Gesù: drawing the mould.

[Claudius]

I have never seriously tried to draw a Guarneri mould because the strong irregularities of the Guarneri del Gesù work, although the drawing method based on the golden ratio from Sacconi gave me very good results with violins, violas and cellos in many years. I think that it succeeded: drawing a Guarneri mould was one of the most interesting artistic trips in my life as a violinmaker, because I found the Amati, Guarneri and the Stradivari roots there. Here my article published in italian (no english at the moment because it's very difficult to find the right words when I'm talking about violins, sorry), where you can read more about my experience and see my drawings: https://www.claudiorampini.com/2025/05/04/guarneri-del-gesu-il-disegno-della-forma/

I'm happy to share the results of my research on the Guarneri mould with you guys, feel free to express your opinions. Try to translate the article using AI, thanks.

 

[HoGo]

I've spent few years (on and off) trying to figure out geometry behind the original form of Amati family and mostly Guarneri....  I've got about dozen mid-era dG violins resized and/or assembled from smaller photographs in photoshop to full size making sure the dimensions match reality and also some CT scans and the consistency of dG work is extremely high the backs are almost interchangeable except the very corners in most examples.

Over this assembly I made my best effort to place circles that would describe the geometry similarly to the four circle method etc. and they show some interesting features but when I overlaid your mould it doesn't fit too well. The lower bouts and corners are too far from the typical Gesu outlines.

Perhaps you used one of the later odd models for your mould? I believe the Ole Bull or even Cannone may not fit the majority of his earlier violins.

[Don Noon]

7 hours ago, Claudio Rampini said:

Here my article published in italian 

Try to translate the article using AI, thanks.

I didn't have to try... my browser is set to translate to English, and it seems to read quite well.

Your construction method, however, is foreign to my lazy way of thinking.  I just take a photo of a violin with a shape that I like, import it into a CAD program, then draw a bunch of tangent arcs or ovals until it comes close.  The form geometry is offset from that.

[JacksonMaberry]

If it results in a form that results in a good sounding violin, then it's a success, and after reading the article and looking at the images it seems like it should, all other things (material selection, arching, grads, etc) being of high quality. Congrats!

I haven't invested as much time as you have in studying the outlines of dG (or Strad for that matter) so I couldn't comment on the form design itself. I'm a Stainer/Serafin/Peter of Mantua weirdo. 

 

[Nick Allen]

11 minutes ago, Don Noon said:

I didn't have to try... my browser is set to translate to English, and it seems to read quite well.

Your construction method, however, is foreign to my lazy way of thinking.  I just take a photo of a violin with a shape that I like, import it into a CAD program, then draw a bunch of tangent arcs or ovals until it comes close.  The form geometry is offset from that.

I like this approach. 

The lazy method often prevails in industry. 

I've always just kind of figured that old violin makers arrived at a shape that is generally pleasing to the eye and I also kind of wonder if they shared their wooden forms and just had a buddy over for wine and dinner and he brought his forms and they just traced them and made new ones, perhaps slightly modifying them in one aspect or another. I mean, we kind of just do that nowadays. 

Efforts to find some answers in the design seem like a lot of wishful reverse engineering at times. And every time we seem to come up with "the system", it always has to be fudged to actually reflect real world examples anyways. 

[Nick Allen]

3 minutes ago, JacksonMaberry said:

I'm a Stainer/Serafin/Peter of Mantua weirdo. 

 

Let's pour one out for this man....

[Claudius]

37 minutes ago, HoGo said:

I've spent few years (on and off) trying to figure out geometry behind the original form of Amati family and mostly Guarneri....  I've got about dozen mid-era dG violins resized and/or assembled from smaller photographs in photoshop to full size making sure the dimensions match reality and also some CT scans and the consistency of dG work is extremely high the backs are almost interchangeable except the very corners in most examples.

Over this assembly I made my best effort to place circles that would describe the geometry similarly to the four circle method etc. and they show some interesting features but when I overlaid your mould it doesn't fit too well. The lower bouts and corners are too far from the typical Gesu outlines.

Perhaps you used one of the later odd models for your mould? I believe the Ole Bull or even Cannone may not fit the majority of his earlier violins.

Thank you for your reply, I was referring mainly to the "Lord Wilton" and the "Alard" GdG and there was a very good fitting. If you can give me your photo references I can try to overlaid using my dwg file.

 

Just now, Don Noon said:

I didn't have to try... my browser is set to translate to English, and it seems to read quite well.

Your construction method, however, is foreign to my lazy way of thinking.  I just take a photo of a violin with a shape that I like, import it into a CAD program, then draw a bunch of tangent arcs or ovals until it comes close.  The form geometry is offset from that.

Thank you for your feedback, now I'm sure that more people can read my article without problems.

I never used violin photos to make a new mould because the optical and the printing aberrations, I got very good results using the golden ratio method. It maybe tricky the first time, but it is not that difficult especially if you are using CAD. Regarding the corner blocks, as I wrote in my article, these parts are the ones that it's almost impossible to determine a rule because it's depending on how you are using your gouge and how you are bending the CC ribs. But the CC and the lower and the higher bouts curves should have very good similarities. 

[JacksonMaberry]

17 minutes ago, Nick Allen said:

I like this approach. 

The lazy method often prevails in industry. 

I've always just kind of figured that old violin makers arrived at a shape that is generally pleasing to the eye and I also kind of wonder if they shared their wooden forms and just had a buddy over for wine and dinner and he brought his forms and they just traced them and made new ones, perhaps slightly modifying them in one aspect or another. I mean, we kind of just do that nowadays. 

Efforts to find some answers in the design seem like a lot of wishful reverse engineering at times. And every time we seem to come up with "the system", it always has to be fudged to actually reflect real world examples anyways. 

As someone who has wasted a lot of fkin time trying to find a "system" (more with arching of particular makers than possible form outlines), I now fully agree with what Nick has said here. Especially the parts I italicized. 

18 minutes ago, Nick Allen said:

Let's pour one out for this man....

Please do! I like to celebrate my own goofiness, and enjoy it even more with friends. 

[David Burgess]

29 minutes ago, Nick Allen said:

I've always just kind of figured that old violin makers arrived at a shape that is generally pleasing to the eye and I also kind of wonder if they shared their wooden forms and just had a buddy over for wine and dinner and he brought his forms and they just traced them and made new ones, perhaps slightly modifying them in one aspect or another. I mean, we kind of just do that nowadays. 

Efforts to find some answers in the design seem like a lot of wishful reverse engineering at times. And every time we seem to come up with "the system", it always has to be fudged to actually reflect real world examples anyways. 

Quite possibly true. I can easily go along with that.

[David Burgess]

Several hundred or thousand years from now, archaeologists will dig up my gas-fired barbecue,  and conclude that it was for the purpose of making burnt offerings to the gods.

[LCF]

1 hour ago, David Burgess said:

Several hundred or thousand years from now, archaeologists will dig up my gas-fired barbecue,  and conclude that it was for the purpose of making burnt offerings to the gods.

That's what happens every time I use mine. 

[Claudius]

Regarding the drawing method based on the golden ratio from Sacconi, I dug into this and I went more times in Rome to the Accademia di Belle arti located in Via di Ripetta, to do an archive search to verify if and when Sacconi was a student of this very important italian academy, as Alfredo Puerari wrote in the Sacconi's book.

Unfortunately I didn't find anything related to Sacconi because some records were destroyed, but I met there the professor Marco Bussagli specialized in artistic anatomy and I asked him if he knew the golden ratio drawing method and Luca Pacioli's book "De Divina Proportione" (you can download a 1509 copy completed with Leonardo drawings from archive.org).

Professor Bussagli confirmed, he knew all about the golden ratio and Pacioli and he is teaching these concepts to his students.

It's very important to know that in the Accademia di Belle Arti of Rome the architectural drawing was taught until the mid-1900s at least, following the Renaissance tradition where a painter or a sculptor could be an architect and viceversa. This is very important when we are talking about proportions.

I had just a suspicion that Sacconi learned to the golden ratio drawing method in the italian academy, now I'm almost certain of this thanks to Professor Marco Bussagli.

The Pacioli's book contains many teachings on how to apply the golden ratio, among these how to draw the latin capital letters, because that Pacioli's drawing method looks like the Sacconi's one. This does not prove that Stradivari, Guarneri, Amati, used this method, but it's important to understand that with this method you can draw everything, educating your eye to the art of proportions. (in the Trattato della Pittura by Leonardo, the proportions teachings is at the first chapter).

After my new Guarneri mould I tried to draw some of the latin capital letters just to verify how to apply the golden ratio method, and here you can see the results with the help of Autocad.

 

 

 

[larry f]

On 6/14/2025 at 4:49 PM, Nick Allen said:

I like this approach. 

The lazy method often prevails in industry. 

I've always just kind of figured that old violin makers arrived at a shape that is generally pleasing to the eye and I also kind of wonder if they shared their wooden forms and just had a buddy over for wine and dinner and he brought his forms and they just traced them and made new ones, perhaps slightly modifying them in one aspect or another. I mean, we kind of just do that nowadays. 

Efforts to find some answers in the design seem like a lot of wishful reverse engineering at times. And every time we seem to come up with "the system", it always has to be fudged to actually reflect real world examples anyways. 

 I agree.

[Claudius]

In the screenshot a more larger image of my Guarneri mould, where you can see the gold ratio proportion applied following the same drawing method from Sacconi and Luca Pacioli (De Divina Proportione). In the next months I'll make a violin with this new mould.

[Andreas Preuss]

To me Guiseppe Guarneri del Gesu is the last important exponent of the Amati tradition. His outlines in their rounded forms are just ‘pure brothers Amati’. (Might be interesting to compare them) 

For the moulds I questioned myself with how much precision they were made to obey underlying geometrical proportions. Last not least some irregularities seen on instruments came eventually through the wear on the forms. This might have been  particularly true for a maker like Guarneri who was capable to ‘improvise’ on all the aesthetic details.

in any case I believe that it is important for a faithful interpretation of any violin of Guiseppe Guarneri del Gesu to understand the execution methods allowing variations in the result which DON’T fit any more precisely into geometrical proportions. Otherwise the result looks like a ‘face lifted’ Guarneri where all the beautiful wrinkles have been smoothened out.

[JacksonMaberry]

55 minutes ago, Andreas Preuss said:

To me Guiseppe Guarneri del Gesu is the last important exponent of the Amati tradition. His outlines in their rounded forms are just ‘pure brothers Amati’. (Might be interesting to compare them) 

For the moulds I questioned myself with how much precision they were made to obey underlying geometrical proportions. Last not least some irregularities seen on instruments came eventually through the wear on the forms. This might have been  particularly true for a maker like Guarneri who was capable to ‘improvise’ on all the aesthetic details.

in any case I believe that it is important for a faithful interpretation of any violin of Guiseppe Guarneri del Gesu to understand the execution methods allowing variations in the result which DON’T fit any more precisely into geometrical proportions. Otherwise the result looks like a ‘face lifted’ Guarneri where all the beautiful wrinkles have been smoothened out.

Agreed 

[HoGo]

I don't have 

21 hours ago, Claudio Rampini said:

Thank you for your reply, I was referring mainly to the "Lord Wilton" and the "Alard" GdG and there was a very good fitting. If you can give me your photo references I can try to overlaid using my dwg file.

I don't have those two in good enough resolution but I have about dozen other dG violins from 30's and just like Hargrave suggested they are so alike that thay possibly came from one single mould. Even Kreisler (one of the larger Gesus) matches them within a mm, just the upper block seems to be extended above form creating a bit longer model, also more overhang and wider edges make it appear larger than it actually is but the CT of ribs pretty much matches the rest.

Here is my drawing of Plowden (there are two identical outlines in the picture, one is flipped to show how little asymmetry there is) and your form overlaid. The upper bout is OK, but the lower bout diverges in places a bit more than I'd like.

Here is my Photoshop screenshot with Plowden outline I created versus all the circles that make up the outline (there is also one ellipse that describes the bout nearly perfectly). There are some interesting ratios between the radii of the main circles but I cannot be certain whether it was intentional or just byproduct of using rounded (venetian or whatever)inch scale for basic dimensions.

I believe I posted those Plowden outlines here on MN some time ago for those who want to use it.

[Claudius]

@Andreas Preuss @HoGo considering that I started my Guarneri drawing without any photos that can help to find some proportions (but the the optical and printing aberrations are still there), and considering how irregular is the Guarneri work, I am happy enough with the results. The lower bouts curves can be corrected very easily without altering the golden ratio proportions, but the most important is that I made the drawing first, then I compared it with some Guarneri photos on the Strad posters just to check to check my work. 

You can do a sort of "reverse engineering" finding the curves utilizing a real size photo, but you'll never know the critical proportions regarding the positions of the point of max thickness of the back, or the point where you can put your FF holes. You can just copy this critical points from the photo, hoping that the real size poster is accurate enough. This kind of copies are the real "face lifted" in my opinion.

The peculiarity of the internal mould construction method is that all your violins made with the same mould will be different, no violin made with the same mould will be a "copy". This drawing method based on the golden ratio is very flexible, this means that you cannot draw a violin mould with a sort of mechanical engineering precision: the final result depends entirely on you. We can use the same method to draw a PG or G mould, and no one of these moulds will be the same. 

Regarding the Guarneri family, I had a Giuseppe figlio d'Andrea violin in my hands and I was impressed on how his work was recalling the Amati proportions. And the same it happens with Guarneri del Gesù, although his irregular work and the different way he had to work his corner blocks.

[HoGo]

11 hours ago, Claudio Rampini said:

considering that I started my Guarneri drawing without any photos that can help to find some proportions (but the the optical and printing aberrations are still there), and considering how irregular is the Guarneri work, I am happy enough with the results.

So how can you call it "Guarneri" if you started just from numbers?

I always wondered about all the talk about huge differences between Strad and del and Amati but if you take model of same size into drawing program like small Amati it will be almost identical in body outline to most of Guarneri family output (excepr corners) and the Grand pattern model will be extremely similar to several Strad moulds except for the corners and the C bout of that Strad changed more radically (though even those radical changes are sometimes less than 1 mm but stand out in the whole outline).

From the violins of dG I put into PC I can't see any big irregularity in his body outline. The only difference is in corners shape but the mid 30' violins all are very close even here. Perhaps he lost his corner templates and just went on freehand in his later period. The files with adjusted photographs and CT scans I have show that many of the violins are so close that you could just swap backs (they are well within 0.5mm). This shows that he likely used just one mould all his life (as Hargrave suggests). The tops are less consistent but that goes with the method they used.

That's why for me the only way to get "Guarneri" mould is to go with one of the originals. There are several drawing schemes out there that will yield violin object with given proportions but to my knowledge they all fail to get you closer to reality than copying the real thing with simple circular arcs. (most of them use some possible random "adjustments" here or there to get closer).

[Claudius]

12 minutes ago, HoGo said:

So how can you call it "Guarneri" if you started just from magic numbers?

To draw a new Guarneri inspired mould I'm starting from the length of the real "Alard" violin body: 353mm. The length of the mould will be about 346mm (considering 5.5mm and 2mm less for edges and ribs). To start the golden ratio graphical process I have to draw a 356.9mm sided square, then a simple triangle and three arcs of circle will define the max lower and higher bouts widths, and the FF hole position and the centre of the max thickness of the back. Now I can proceed to find the other points/proportions as in the drawing in my previous message. This method works with all the cremonese classic instruments. My assumption is that you have to draw your new mould first, then you can compare it with your poster and photos in real size, I followed this way for all my instruments I made in my career.

I think that Guarneri used the same mould and the same proportions for his violins, although his workmanship varied a lot with the late instruments.

[HoGo]

This construction will give you reatio between width of lower and upper bouts of 1.23 (sqrt(5)-1) while in reality with dG violins that ratio is much very close (or equals) to 1.25 or 5/4.

BTW, where is the golden section in that geometry? I see some roots of 5 emerging but no phi. (haven't had the time to study it deeper)

[Claudius]

1 hour ago, HoGo said:

This construction will give you reatio between width of lower and upper bouts of 1.23 (sqrt(5)-1) while in reality with dG violins that ratio is much very close (or equals) to 1.25 or 5/4.

BTW, where is the golden section in that geometry? I see some roots of 5 emerging but no phi. (haven't had the time to study it deeper)

This construction is giving us about 160mm and 197.5mm: the width of the upper and lower bouts of the mould respectively. I'm referring to the dimensions of the GdG Alard 1742 from The Strad poster for my Guarneri mould.

Regarding the golden ratio, this is my tutorial regarding the PG Strad mould, this can be used to draw the Guarneris or the Amatis moulds : https://www.claudiorampini.com/Varie/Disegno_Forma_PG_2021.pdf

[Marty Kasprzyk]

On 6/14/2025 at 6:49 PM, Nick Allen said:

I like this approach. 

The lazy method often prevails in industry. 

I've always just kind of figured that old violin makers arrived at a shape that is generally pleasing to the eye and I also kind of wonder if they shared their wooden forms and just had a buddy over for wine and dinner and he brought his forms and they just traced them and made new ones, perhaps slightly modifying them in one aspect or another. I mean, we kind of just do that nowadays. 

Efforts to find some answers in the design seem like a lot of wishful reverse engineering at times. And every time we seem to come up with "the system", it always has to be fudged to actually reflect real world examples anyways. 

That's what I've always thought too.  

The earliest original instruments might have been made by simply bending the ribs to shape.  This was done without having to first make geometric construction drawings followed by making molds from these drawings and then bending the ribs to fit the molds to finally match the original contruction drawings.

Subsequent generations of makers then just copied these first bent rib instruments and made their own modifications to them by mearly bending the ribs a little differently.  Molds were then eventually made to enable these shapes to be reproduced consistantly and later makers copied them.

Attached is a sequence of four photos showing how the original bent ribs might have been made without any drawings:

[Nick Allen]

1 minute ago, Marty Kasprzyk said:

That's what I've always thought too.  

The earliest original instruments might have been made by simply bending the ribs to shape.  This was done without having to first make geometric construction drawings followed by making molds from these drawings and then bending the ribs to fit the molds to finally match the original contruction drawings.

Subsequent generations of makers then just copied these first bent rib instruments and made their own modifications to them by mearly bending the ribs a little differently.  Molds were then eventually made to enable these shapes to be reproduced consistantly and later makers copied them.

Attached is a sequence of four photos showing how the original bent ribs might have been made without any drawings:

That's a pretty neat rib bending method there. 

I think, just personally, that when viewing the development of classical violin design, Occam's Razor is particularly relevant. 

[John Harte]

On 6/16/2025 at 6:30 AM, Andreas Preuss said:

To me Guiseppe Guarneri del Gesu is the last important exponent of the Amati tradition. His outlines in their rounded forms are just ‘pure brothers Amati’. (Might be interesting to compare them) 

On 6/16/2025 at 10:30 AM, Claudio Rampini said:

Regarding the Guarneri family, I had a Giuseppe figlio d'Andrea violin in my hands and I was impressed on how his work was recalling the Amati proportions. And the same it happens with Guarneri del Gesù, although his irregular work and the different way he had to work his corner blocks.

There is an interesting PDF that explores this that appears here: https://strad3d.org/articles.html  Under the heading More Research, see “Two Forms: Francois Denis”.  See p.11 for a discussion on Amati patterns and their link to del Gesu etc..