Proceedings e report - Firenze University Press

4. Conclusions
chrome yellow
WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
mars red
minium
raw Sienna
0 2 4 6
dE CMC
Fig. 2. Colour shift over time (1 year) for samples (B)
The agreement of the two inter-compared spectrophotometers is depending on the uniformity of the
samples, but even for some samples of bad uniformity as Solferino lake the agreement is good in total
colour differences values. Regarding the effect of irradiation on the colour of samples (A), total colour
differences are lower than 5 dE* units (i.e. small colour differences) except cobalt blue, ochre yellow,
and rabbit-skin glue.
The influence of irradiation on the colour shift over time of samples (B) is specific for the type of
sample and it is only quantitative in terms of lightness, chroma and hue. The colour shift increases
with the dose ratio and it is not influenced by varnish except samples prepared with raw Sienna.
Acknowledgments
Acknowledgments are due to COST Action IE0601 for the STSM of M.Cutrubinis at ARC-Nucléart
by which the collaboration was possible.
References
1. Tiano, P.: “Biodegradation of Cultural Heritage: Decay Mechanisms and Control Methods”.
http://www.arcchip.cz/w09/w09_tiano.pdf.
2. HunterLab (2008): Maximizing Inter-instrument Agreement.
http://www.hunterlab.com/appnotes/an06_05.pdf.
3. Brainard, D.H. (2003): “Color appearance and Color Difference Specification”. In Shevell, S.K.
(Ed.), “The Science of Color (2 nd edition)”. Oxford UK: Elsevier.
4. ISO 105 Part J03 (2006): Calculation of colour differences.
5. Rizzo M.M., Machado L.D.B., Borrely S.I., Sampa M.H.O., Rela P.R., Farah J.P.S., Schumacher
R.I. (2002): Effects of gamma rays on a restored painting from the XVIIth century. Rad Phys
Chem. 63 (3-6): 259-262.
6. Negut, D.C., Ponta, C.C., Georgescu, R.M., Moise, I.V., Niculescu, Gh., Lupu, A.I.M. (2007):
Effects of gamma irradiation on the colour of pigments. Proc. of SPIE Vol. 6618: 66180R1-10.
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