Thank you for sharing

Violin making depends on having good tools. Tools are traditionally prosthetic devices, extending what we might otherwise not be able to do with our hands. A hand plane guides us to cut straight lines, as do rulers marking their paths; a gouge embeds gentle arcs in an arching, like the compasses outlining their contours.

The familiar tools of the violin maker’s workshop are increasingly augmented by those from the digital world: CT scanning, visualisation software, 3D printing and computer-numericallycontrolled (CNC) machining. These new resources can help to improve the luthier’s essential understanding of canonical instruments from the ‘golden age’ of violin making. A case in point is the excellent, minutely detailed micro- CT scanning of the ‘Baron Knoop’

Bergonzi violin featured in this issue of The Strad, which gives invaluable insights into the instrument, revealing everything from the wood grain to the internal craftsmanship.

Digital tools need data to be useful: ever larger digital files that provide information about instrument geometry. This is one piece in the larger puzzle of decoding the work of the great violin makers. But to have excellent data, you need renowned instruments to be scanned, and you need the scan data to be shared with you. Where is this data going to come from, and who is going to share it?

It’s not easy to obtain a good dataset, because even though high-resolution scanning and data dissemination are technically feasible and practical, there are associated beliefs, biases and superstitions that change slowly. This counter-productive logjam needs easing. It remains a challenge to facilitate this dissemination, use the data responsibly and well, and disabuse ourselves of unwarranted fears that impede its use.

To give a recent example, one of the authors (Harry Mairson) was interested in making a Brothers Amati viola model, and followed an email chain of communications to track down the industrial CT scan of such an instrument. Ultimately he was told that the owner of the data simply would not share it. It was ‘proprietary’. This is not uncommon.

Let us briefly praise this digital information. Numerous famous instruments have had industrial CT scans, a data resource so precise that it can show how uniformly the glue in a neck joint is spread out. Having CT data of a great instrument is like having it in your shop to measure: to see the outline, the corners, the plate thicknesses, how the f-holes sit in the arching, and to see their shape without the distortion of frontal photographs. What’s the overstand, or the stop length, on that famous cello? You can go and measure it. It’s a fantastic study resource.

Moreover, digital archiving protects famous and irreplaceable stringed instruments from damage, while increasing access to information about them. An instrument needs only one good scan. Then, subsequent measurement and visualisation comes from the dataset, not the artefact.

With 3D printing we can enhance this non-invasive curatorship and access, even without a computer.

The technology to obtain this digital information took years to develop. But it remains an even bigger political – and effectively, a psychological – challenge to share this information. Why isn’t that access facilitated, open to those professionals who need and want it?

The authors collaborated in 2017 to CT-scan the 1700 ‘Stauffer, ex-Cristiani’ Stradivari cello at Cremona’s Museo del Violino. Since then we’ve sent the data to any number of violin makers who would like to see it. The Museo now has a 3D print of the body which you can touch, and from which you can measure the archings – something that, for conservation reasons, couldn’t be repeatedly allowed through examination of the original.

What downside is there to this kind of dissemination? What impedes it?

CT scans allow precise measurement and visualisation

THERE’S AN UNCONSCIOUS FEAR THAT CT SCANNING WILL GIVE AWAY A VIOLIN’S SOUL

The violin is humanised with anthropomorphic imagery – belly, back, ribs, neck, heel, head (scroll). There once was a superstition that if you were photographed, your soul would be stolen away in the process – and there’s a commensurate, unconscious fear that CT scanning will give away a violin’s soul (anima being Italian for ‘soundpost’). But geometric data is not the only élan vital, and hardly sufficient to make a great instrument. So much else is involved: adapting to the individual qualities of each unique piece of wood, joinery, varnish, set-up, playing-in. Recall the ironic title of Simone Sacconi’s famous book, The ‘Secrets’ of Stradivari. There are not really any secrets – only countless complementary steps, executed flawlessly.

It does not stand to reason that a CT scan of the ‘Stauffer, ex-Cristiani’, and what it reveals about this instrument, compromises the inherent value of the original. Nor would dissemination of similar data for other famous instruments cause such a calamity. Were any luthier to arrive at the Museo with a modern copy of this cello, even one seemingly indistinguishable from the one in the museum, the luthier would be welcomed, praised and congratulated. But if this talented luthier proposed an exchange of instruments, the answer is obvious: of course not! There can only be one historical original and the Museo has it.

This law of physical (and philosophical!) identity is ironclad – regardless of your lutherie prowess, you simply cannot make another original. You can only make an original yourself, by your own hand.

Another common fear is that factories will mass-produce an instrument whose geometry has been revealed in all its detail, with economic repercussions. (There are often xenophobic and racist overtones to this fear, like many fears, though the national or ethnic identity of the offending party has changed over the centuries.) Yet geometric data alone will not make a great mass-produced instrument. A good design is a fine start, but there are so many other demanding and costly construction issues to address. Even if these issues are ignored, and the product is mediocre, we could also fear that such a factory would use the imprimatur of CT data to claim its instruments ar the real thing, accurate to the last fraction of a millimetre. But a dishonest practitioner can easily claim to be doing so already, without ever having so much as glimpsed the CT data!

Left–right The original ‘Stauffer, ex-Cristiani’ Stradivari cello; a CT scan of the front; and a copy of the cello made by 3D printing

Owners of famous and fabulously expensive instruments may also fear that the knowledge of defects, revealed by this technology – soundpost cracks, wood damage, and hidden restoration, perhaps done badly – will depreciate their value.

But no one is going to buy a costly instrument without obtaining such information, just as no one would buy expensive real estate without a comprehensive survey of its foundation and structure. To forbid digital surveying of such an instrument only raises suspicions of defects, rather than addressing them.

TO FORBID DIGITAL SURVEYING OF AN EXPENSIVE INSTRUMENT ONLY RAISES SUSPICIONS OF DEFECTS

In our contemporary world of perfect information, there is no longer any alternative. The CT scan of the ‘Stauffer, ex-Cristiani’ revealed the deterioration and restoration that you would expect in a musical instrument that is over 300 years old, including woodworm in the belly, chest and soundpost patches, rib doubling, and even doubling on the back. Regardless, it remains a remarkable and beautiful cello, with a devoted following among luthiers and musicians.

One might also hesitate to share scan data because it seems costly to obtain.

The printed copy is a study object allowing hands-on access to the plates

CELLO PHOTO AND CT SCAN COURTESY MUSEO DEL VIOLINO. PRINTED COPY COURTESY HARRY MAIRSON

But on the contrary, an industrial CT scan of a musical instrument can be obtained for small thousands of euros – not an inconsequential sum, but hardly an insurmountable one. The true value of such a scan is not in the cost it incurs, but in the exclusivity of access: one has to ‘know somebody’ before the scan can occur in the first place. This was true when the ‘Stauffer, ex-Cristiani’ scan was done. But what began as only a professional interaction and negotiation between the authors became a friendship. We are ready to share the example of our interaction, and the fruits of the subsequent collaboration, as a model for others to act similarly.

Unlike CT-scan data, however, its analysis can be expensive. For example, the violin making world has numerous books on famous instruments, containing remarkable information. Its analysis and presentation requires many hours of labour, and the authors and publishers of those books deserve remuneration for their work.

In addition, there may be significant investment in hardware and software needed for that analysis. But there are inexpensive ways to find tractable and serviceable alternatives – CTvisualisation freeware, for example, instead of proprietary software. In that way, more people will have access to better information.

Nonetheless, we do not support creating websites open to anyone, with free access to high-resolution CT data. Institutions and private owners have significant costs in making information available. Equally important, when there is even a moderate charge for something, you value it more (‘I paid for that!’). In becoming recipients of that knowledge, we are simultaneously called upon to act responsibly with it.

We encourage institutions and private owners of renowned instruments to make digital data available, on request, to motivated researchers and makers.

Instrument owners have the right to know the purpose of requests for digital information; those who make such requests support this relationship by acting responsibly with what is shared.

The goal is not a restrictive control of data, but the responsible dissemination of knowledge –a dissemination that can only succeed if all involved understand that it is in their best interests – and, moreover, in the best interest of advancing knowledge for the larger community of makers, researchers and players.

Historical instruments are owned by individuals and institutions, but the historical record of their craftsmanship should not be proprietary. It is, as the Unesco designation of Cremonese lutherie specifically underlines, a cultural heritage of humanity. The very act of sharing this remarkable digitised heritage can help make better instruments, help make friends, and help make us better people.