Desirability of even Plate tone...
.... Put plainly, the plates must exhibit an even tap tone all over the vibrating surface of the top and also the back plate. Besides this, the back plate'sTap Tone frequency must be 198 HZ all over; and the top plate (Belly) (and bass bar all along its length) should be at 176 HZ.
...If the plates are not even, the instrument will not produce sound at the highest professional level, period! Please see other articles on how to do this...
...Here is a graphic example of the coloration effects of U.V. light. Both top plates are made of the same wood; both started out just as white as the one on the right. This probably represents two weeks in my U.V. exposure box.
...The exact acoustical effect is unknown, but considered a positive thing. As you see, the color will be richer when varnished after UV exposure (tanning).
..Please see current articles in acoustical relationships section, on possible 'ideal' tap tone tuning of plates.
...Also be aware, when selecting the wood for your violin plates, that there is an ideal Wood Tone and Rub Tone for each plate wood, that will largely determine the ultimate success of your violin. For the top plate, we want a 198 HZ Wood Tone wood with a # 22 Rub Tone. For the back plate, we want a 242 HZ Wood Tone wood with a # 22 Rub Tone. (2017... result of extensive wood selection research).