Density differential versus median density of all top and back plates.

<p>Density differential versus median density of all top and back plates.</p

Density maps of the top (A) and back plates (B).

<p>The contemporary violins are presented on the top row, and the classical Cremonese on the bottom row. The violins have been anonymised. Scales are given in kg/m3. The central violin in the lower row has had more repair work than the other antique violins as evinced by reduced thickness (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002554#pone-0002554-g001" target="_blank">Figure 1</a>.) and increased densities. The dark areas at the centre of the lower third of all violin tops are metal artifacts from the string ends. The dependency of the measured density on plate thickness was eliminated in the quantitative analysis.</p

Thickness maps of the top (A) and back plates (B).

<p>The contemporary violins are presented on the top row, and the antique on the bottom row. The violins have been anonymised. Scales are given in mm. The fourth instrument on the upper row is a viola, which typically is thicker than a violin (image size has been reduced to match that of the violins).</p

Regions of interest (ROI's) on violin plates.

<p>Five different ROI's of 100×100 pixels were defined, carefully avoiding repair work. The same areas were taken from the top and back plates.</p

Table of instruments studied.

<p>Table of instruments studied.</p

Density maps in gram/liter of the back plates.

<p>Density maps in gram/liter of the back plates.</p

Instruments in the former study.

<p>All were violins, except Borman1995, viola.</p

Comparison of the median density between modern and antique back and top plates from this study.

<p>Error bars indicate median values and the 95% confidence intervals.</p

Correlation of density measurements between the CT scanners of Leiden and New York City (NYC).

<p>Correlation of density measurements between the CT scanners of Leiden and New York City (NYC).</p

Graph comparing the median density by country of the back and top plates and summed modern instruments.

<p>Country-Quantity: I-1, Italy (other than Cremona); N-6, the Netherlands; F-1, France; GA-5, Germany/Austria; Gdg-3, Italy (Guarneri del Gesu); S-2 Italy (Stradivari); M-12, Modern instruments.</p