TESTING FROM IMAGES

Testing wood from digital images

A typical photographic image

A typical scanned image

Investigative tree-ring analysis on Musical Instruments

Peter

Ratcliff

DENDROCHRONOLOGY Ltd

from PHOTOGRAPHS

VIOLIN

CELLO

VIOLA

VIOL

LUTE

LYRA

GAMBA

GUITARS

DOUBLE-BASS

"High resolution digital images are now enabling testing without the need for travel"

 

"Images can be stored digitally for later re-assessment if required"

 

"both scanned and photographic images are used, and have proved highly successful"

 

"Instant digital communication and rapid dendro-testing can truly influence a decision"

With the increasing ease in which good quality, high resolution digital images can be produced, it has never been so easy commissioning a test. Analysing instruments via the Internet have considerably reduced processing and travel costs, making initial testing affordable.

 

When picture quality is high, revealing sharp tree-ring boundaries over the whole section to be tested, the accuracy of measurements is second to none.

 

As a distinct advantage from testing with microscopic equipment, files can be stored digitally for re-assessment at a later date if required.

 

Both photographic and scanned images are used for testing. Scanners, equipped of a CCD (charged-coupled device) sensor are often highly suitable, as they allow for a certain amount of depth of field, which those with a CIS (contact image sensor) don’t. Inexpensive flatbed scanners of the Epson Perfection series, such as the V33 can produce excellent suitable images. These tend to be more successful when the varnish of the instrument is of a lighter shade.

 

There is no set number of images required for testing, but sharpness and high resolution are naturally required in order to collect accurate measurements from the rings. Instruments showing particularly tight growth rings may need more advance photographic equipment than most ordinary cameras can provide. Most violin shops now have in-house photographic studios and are able to supply the best possible images.

 

The tree-ring measurements are gathered from a specially designed software module, where enlarged images are loaded on. With ring spacing ending up appearing on screen as distances of several centimetres, exceedingly accurate dimensions can be recorded.

 

Several projects, including research for "The Golden Age of Violi-Making in Spain and "The Girolamo Amati Violin in the Galleria Estense" have been carried out in collaboration with fantastic violin photographer Jan Roerhmann. Jan is also available for shooting high quality images for dendrochronological purposes.

 

Please send your high resolution images to: violin.dendro@yahoo.com for an initial assessment

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