The tones were determined every several days (see dots on lines, which are data points) by comparing to calibrated wood tone strips. The test results are the apparant tone as compared to tuned wood strips, but the conclusions I believe we can draw from this test are these:
the U.V. light exposure caused an increase in the apparent tone;
that the tone steadily increased to a maximum and then held;
that more layers of this test ground resulted in increases, but less of an increase each time (that is the first ground coat made the biggest increase and each subsequent layer had a smaller effect). [ In the test above the first increase was 5 units (musical half tones) vertical, the second 4 units and the third only two units.]
Further: The bare wood (untreated strip) was fully 'develped' after thirteen days and the samples with the test ground layer applied were fully 'developed' after twenty one days.
This suggests that a violin should be exposed to U.V. light after it is completed and varnished, until it reaches this equalibrium point of no further change and that the frequencies then should be our goal frequencies rather than random results.
