Proceedings e report - Firenze University Press

WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
the weight variations are small, approximately 0,5 g that is 0,1% of the violin weight. An interesting
thing happened after concerts. Usually the performance room is drier than the exhibition case, that is
why the violin loses weight, but, after being in the case again, it continued to lose weight
notwithstanding the increased relative humidity of the air. It has been assumed that the influence of the
climate inside the case was great. That is why it is necessary to measure the climatic conditions inside
the sound chamber (the empty space between the two boards) during performances (fig.4).
RH%, T°C
50
47,5
45
42,5
40
37,5
35
32,5
30
27,5
25
22,5
20
17,5
15
13.40.48
RH%
T °C
The violin is out the box
15.36.00
Trabucco ricomincia a suonare
(prove) nella sala prove,
accordatura
Time
189
The violin is in the reharsal hall
The violin is in the
performance room
17.31.12
Concert
starts
Concert stops
Encore
The violin is in its case
Fig. 4: climatic conditions inside the violin’s sound chamber during a performance.
The analysis of weight variation during a performance is shown in Fig. 5; the violin loses about 1 g
during the concert itself because of the different climatic conditions (fig 4). After this extraordinary
event, the required time to regain the original weight, which is considered the equilibrium weight, is
about one month notwithstanding that the climatic conditions in the conservation case are constant (fig
5).
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
RH%, T°
Equilibrium violin weight before the concert 433,10 g.
Violin weight after
the concert: 432,12 g.
15/12/07 0.00
16/12/07 0.00
17/12/07 0.00
18/12/07 0.00
19/12/07 0.00
20/12/07 0.00
21/12/07 0.00
22/12/07 0.00
23/12/07 0.00
24/12/07 0.00
25/12/07 0.00
26/12/07 0.00
27/12/07 0.00
28/12/07 0.00
29/12/07 0.00
30/12/07 0.00
31/12/07 0.00
1/1/08 0.00
2/1/08 0.00
3/1/08 0.00
4/1/08 0.00
5/1/08 0.00
6/1/08 0.00
7/1/08 0.00
8/1/08 0.00
9/1/08 0.00
10/1/08 0.00
11/1/08 0.00
12/1/08 0.00
13/1/08 0.00
14/1/08 0.00
15/1/08 0.00
16/1/08 0.00
17/1/08 0.00
18/1/08 0.00
19/1/08 0.00
time
Equilibrium weight reached
g.
T°
RH%
Weight
Fig. 5: time to regain the equilibrium weight after the concert.
3.2. Measuring tuning forces
The equipped bridge gives useful data on the forces produced during tuning (fig 6).
19.26.24
433,4
433,2
433
432,8
432,6
432,4
432,2
432