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.
The current validation instrument’s owner-supplied identity and ruler measurements are held separately from the blind photographic comparison and are used only for the final accuracy audit.
Validation instrument record
Hesketh reference violinOwner-confirmed working identity, kept separate from the blind photographic comparison.
The established Hesketh register is 353 mm back length, 165 mm upper bout and 205 mm lower bout. Only the 353 mm back length supplies image scale. The two recorded bout measurements are withheld from image processing and used afterwards to audit accuracy; the unrecorded physical C-bout is excluded from scoring.
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 featuresComplete the measurements to compare the image-derived bouts with the physical register.
Accuracy auditNot yet calculated. The audit will report each signed bout error without changing or correcting the photographic result.
Identity safeguardThe Hesketh working identity is a validation label, not an app-generated attribution. Country, school, maker and date remain withheld from the blind result.
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.
Valuation status
Not assessed in this validation phasePhase 8.3 tests capture reliability, repeatability and dimensional accuracy. It does not transfer a valuation or market evidence from any previous instrument.
Recommended action
No attribution issued at this stageComplete the dimensional validation first. Any later maker, origin or value opinion must use instrument-specific evidence and physical specialist examination.
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.
Save captures
Seven numbered photographs. Tap a photograph or its button to save that item.
Safari cannot confirm whether an item was finally saved, so the app does not use a completion counter. Save whichever numbered photographs you require.
