Versão em português
N.º 9
2009
pp. 5-11

 

< Previous Next >

Article
Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy)

Giovanni Cavallo

University of Applied Sciences of Southern Switzerland, Dept. Environment, Construction and Design, LTS, Trevano P.O. Box 12 CH-6952 Canobbio (Ticino)

giovanni.cavallo@supsi.ch

Abstract

Many case studies report the alteration of the pigment azurite into paratacamite on wall paintings in Europe (for instance in Italy, Portugal, Austria). The analytical research performed on the 16th century wall paintings in the St. Alessandro church at Lasnigo (North Italy) pointed out an irregular and inhomogeneous alteration of azurite. It is well known that azurite can transform into malachite when the humidity is high and in alkaline conditions and into basic copper chlorides (atacamite, paratacamite, clinoatacamite) when solutions containing chlorine ions are present. X-ray diffraction allowed to refer the green compounds to paratacamite. The remaining surfaces painted with azurite do not reveal any trace of alteration despite of the presence of chlorine; a few traces of azurite have been found inside the direct incisions of the Crucifixion painted scene where the original blue pigment was completely lost. The microclimatic conditions seem to play an important role in the process in addition to the presence of water and chlorides. The surface where alteration occurs is the only one to be cyclically heated by the solar radiation, causing the transport of the solutions containing chlorides. The relationship between the environment and the chemical processes occurring represents an important issue to be developed.

Keywords

Azurite
Paratacamite
Wall paintings
Lasnigo

Language

English

DOI

10.14568/cp9_2

Download

PDF | Additional material

Download citation

RIS | Endnote

Citation

Conservar Património | APA | Chicago | NP405 | ABNT

Conservar Património:
Cavallo, G., 'Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy)', Conservar Património 9 (2009) 5-11, https://doi.org/10.14568/cp9_2.

APA:
Cavallo, G. (2009). Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy). Conservar Património, 9 5-11. DOI:10.14568/cp9_2.

Chicago:
Cavallo, Giovanni. 2009. "Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy)." Conservar Património 9:5-11. doi:10.14568/cp9_2.

NP405:
CAVALLO, Giovanni – Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy). Conservar Património. [Em linha]. 9 (2009) 5-11 [Consult. ]. Disponível em WWW: <URL:https://doi.org/10.14568/cp9_2>. ISSN 21829942.

ABNT:
CAVALLO, Giovanni. Alteration of azurite into paratacamite at the St. Alessandro Church (Lasnigo, Italy). Conservar Património, Lisboa, v. 9, p. 5-11, 2009. Disponível em: <https://doi.org/10.14568/cp9_2>. Acesso em: .

History

Received: 2009-03-05
Revised: 2009-04-28
Accepted: 2008-10-14Online: 2017-10-3
Publication: 2010-1-9

References

1 Bruni, S.; Guglielmi, V., 'La spettroscopia Raman per lo studio delle opere d'arte', La chimica e l'industria 87 (2005) 68-73.

2 Bruni, S.; Guglielmi, V., 'Application of a compact portable Raman Spectrometer for the field analysis of pigments in works of art', in Lasers in the Conservation of Artworks, ed. J. Nimmrichter, W. Kautek, M. Schreiner, Springer, Berlin (2007) 407-414.

3 Cavallo, G.; Dal Bianco, E.; Luzzana, G., 'I dipinti murali cinquecenteschi della chiesa di Sant'Alessandro a Lasnigo: nuovi dati sui materiali originali e le tecniche esecutive', in Colore e Arte: Storia e Tecnologia del Colore nei Secoli, ed. M. Bacci, Patron Ed., Bologna (2008) 255-264.

4 Gettens, R. J.; Fitzhugh, E., 'Azurite and Blue Verditer' in Artists' Pigments, vol. 2, ed. A. Roy, Washington, National Gallery of Art, Washington (1993) 23-35.

5 Dei, L.; Ahle, A.; Baglioni, P.; Dini, D.; Ferroni, E., 'Green degradation products of azurite in wall paintings: identification and conservation treatment', Studies in Conservation 43 (1998) 80-88.

6 Seccaroni, C.; Moioli, P., Fluorescenza X, Nardini Ed., Firenze (2002) 154-157.

7 Sharkey, J. B.; Lewin, S. Z., 'Conditions governing the formation of atacamite and paratacamite', The American Mineralogist 56 (1971) 179-192.

8 Torraca, G., 'Tecnologia delle malte per intonaci e della conservazione degli intonaci antichi', in Diagnosi e Progetto per la Conservazione dei Materiali dell'Architettura, Ed. De Luca, Roma (1998) 203-221.

9 Giovannoni, S., Private communication (2007).

10 Bianchetti, P.; Santopadre, P., 'Alterazione dei pigmenti nei dipinti murali: la trasformazione dell'azzurrite in paratacamite', Bollettino ICR 8-9 (2004) 76-86.

Stable url: https://doi.org/10.14568/cp9_2


< Previous Next >
ARP | Associação Profissional de Conservadores-Restauradores de Portugal