Loose guide only — the complete outline may sit anywhere inside it with a visible margin
Automatic alignment
Photograph review
Side-view calibration
Predicted resting angle
Mark four side-view points
The same photograph remains the arching record. For this development test, tap two points along the back-edge reference, then the nut/string contact and bridge-top contact. The finished app is intended to detect these automatically.
Tap the back edge near the upper bout.
No angle calculated yet.
One measurement only
Back length
Measure the back once
Use a firm metric ruler. Measure in a straight line from the top edge beside the neck to the lowest edge of the back. Do not include the button and do not follow the arching.
mm
This single value supplies the scale. The app derives the other body dimensions from the accepted square-on photograph.
Independent image-first assessment
Appraisal result
—/100 capture quality
Capture quality
Required views
Image alignment
Image clarity
Automatic body measurements
Scale reference
Bout measurements are image-derived estimates. The back length is the only manual measurement. Measurements are withheld when the outline or camera pose is unreliable.
Independent visual observations
Body outline and proportionsSuitable for established outline comparison. The three-instrument validation achieved a 3.348× repeat/different separation margin.
Corners, edgework and purflingCoarse geometry may support a conclusion; fine corner morphology is withheld because repeatability failed.
F-holesPosition, inclination, stems, eyes and wings are recorded for review. This channel is not yet allowed to determine attribution.
Scroll and pegboxFront and side morphology recorded. Comparison status: research channel.
Arching, wood and varnishVisible profile, colour, transparency, flame, wear and apparent antiquing can be described; varnish chemistry cannot be established from photographs.
MeasuredProvisionalWeak evidence withheld
Four-school comparative register
The figure below is the mean absolute percentage difference across the four published body measurements. Lower means geometrically closer. It is not a probability, confidence score or attribution.
Rank
School
Reference
Back
Upper
C
Lower
Mean difference
Comparison will appear after measurements are available.
Attribution remains withheldThe register contains four measured Scottish, four English, four French and three German controls. German measured coverage is therefore smaller and the whole register remains provisional. Dimensional closeness cannot establish country, school or maker; authenticated photographic morphology and physical construction evidence remain necessary.
German visual and construction context
The following published records provide qualitative context but are excluded from the dimensional ranking because a complete set of four comparable body measurements is not available: Louis Noebe (1881), The Strad, April 2026; and Anton Bachmann (1790), Ludwig Neuner (1896), Otto Möckel (1918), Michael Strobl (1914) and Michael Dötsch (1914), “Berlin Calling,” The Strad, September 2025, pp. 56–63. The Markneukirchen articles of April 2011 and August 2021 provide regional and construction context rather than individual measured controls.
David Rattray, “David Stirrat,” The Strad, December 2019, pp. 63–65.
David Rattray, “Thomas Hardie,” The Strad, vol. 128 no. 1523, March 2017, pp. 57–59.
David Rattray, “Matthew Hardie,” The Strad, vol. 129 no. 1537, May 2018, pp. 61–63.
David Rattray, “Alexander Smillie,” The Strad, March 2025, pp. 63–65.
Albert H. Cooper, The Cooper Collection, vol. 2, Ashford Publications, 1998: Richard Duke, Joseph Hill, Richard Tobin and Betts-associated Bernhard Simon Fendt records.
Published French measured references: Nicolas Lupot (1824), Nicolas-François Vuillaume (1859) and Auguste Sébastien Philippe Bernardel (1845), from The Strad; Georges Chanot, The Cooper Collection. The Chanot heading dates the instrument c.1865 while the reproduced label appears to read 1855; that discrepancy is retained rather than resolved by the app.
Published German measured references: Gabriel David Buchstetter (1767), The Strad, March 2014; Aegidius Klotz (1791), The Strad, April 2014; Michael Dötsch (1923), The Strad, April 2025.
John Dilworth, “The grand old Duke of lutherie”: independent historical and workmanship evidence for the varied output of Richard Duke’s workshop.
William Henley, Universal Dictionary of Violin & Bow Makers, first edition, 1959, p. 227.
Brian W. Harvey, The Violin Family and its Makers in the British Isles, Oxford University Press, 1995, pp. 172–181. Context and authenticated Scottish plates only.
Bonhams London, Lot 68, 7 August 2013: catalogued James M’Intosh, no. 174, 1859; 360 mm back. Incomplete dimensions, so excluded from four-measure ranking.
Instrument record
McIntosh reference violinOwner-confirmed working identity. The maker attribution itself remains subject to specialist verification.
350 mmConfirmed back length
Smaller full sizeOwner description
Historical development entry: Violin 2 — McIntosh, formerly recorded as 345 mm. The present owner-rechecked 350 mm measurement supersedes it. Violin 4 is a separate unidentified instrument.
Blind classification status
WithheldCountry or school
WithheldApproximate date
UndeterminedIndividual / workshop / trade
Not calculatedCalibrated confidence
Candidate maker or workshop shortlistNot issued: authenticated English and Scottish photographic reference coverage is not yet sufficient.
Supporting featuresMeasured 350 / 165.2 / 110.7 / 202.4 mm geometry is ready for comparison. Owner-recorded flat arching and carefully inlaid purfling are more compatible with Henley’s later, post-1869 description than with his early high-arched Stainer model.
Conflicting featuresThe one-piece back is mentioned by Henley in connection with early instruments, although he does not state that it is exclusive to that period. The observed golden-brown varnish does not closely match his greyish-varnish description. These differences remain visible and are not averaged away.
Period compatibility—not a dateLater M’Intosh model provisionally favoured. This is comparison with a written historical description; it does not authenticate the maker or establish a manufacturing date.
The label, certificate and owner’s suggested maker have not influenced this image-first assessment.
Documentary evidence
Not yet combinedAdd labels, certificates, expert opinions and provenance only after the independent assessment.
Indicative valuation
£4,000–£6,000Brompton’s estimate · 10 Feb 2024
£3,800Documented auction reserve
£2,500Voigts purchase · early 1990s
UnsoldRecorded auction outcome
These are documentary facts, not an app-generated valuation. Brompton’s recorded “James McIntosh”, a £4,000–£6,000 estimate and £3,800 reserve on its signed contract dated 10 February 2024. The instrument was unsold. A present-day valuation remains to be established from dated comparable sales and specialist examination.
Recommended action
Specialist British-school opinion recommendedAsk the specialist to reconcile the Voigt certificate with the later English opinions, examine construction internally and physically, and provide a current insurance or sale valuation.
Documentary evidence
Added only after the image-first result
This information is stored separately so a label or owner belief cannot bias the initial visual assessment.
