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Art Restoration

 

Prof. Enzo Ferroni (1921-2007), co-founder of CSGI, was one of the first scientists to apply a scientific approach to the conservation of cultural heritage. After the catastrophic flood of the river Arno that hit Florence in 1966, Ferroni began to collaborate with restorers and conservators, using his physical chemistry background, in order to help them save some of the masterpieces of Italian Art. Since then, CSGI became one of the first research institutes to recognize the potential of applying nanoscience to art conservation and created an extended network with conservation centers and academic institutions worldwide. An overview of the main fields of conservation of cultural heritage currently addressed by CSGI is reported in the following sections.


Units Involved in This Research Area



Florence - Headquarter


Siena - STCDB


Projects Related to This Research Area



NANOFORART


TEMART


TECON

 

Consolidation of Wall Paintings

Calcium carbonate constitutes the matrix of wall paintings, in which pigment grains are embedded. As a result of the combined action of natural weathering and environmental pollution, wall paintings usually exhibit flaking of the paint layer or powdering of the surface. Therefore, in order to recover both mechanical and aesthetic properties, a consolidation intervention is usually required. A significant improvement over traditional consolidation methods has been made by CSGI, which developed alcoholic dispersions of inorganic hydroxide nanoparticles for stones and wall paintings. Nanometric particles easily penetrate into porous materials and quickly react with atmospheric carbon dioxide, forming a binder for degraded surfaces. This technology has been successfully applied to many case studies over the years and new synthetic pathways and formulations are currently under study in the search for more and more effective consolidating systems.




Cleaning of Stones and Wall Paintings

The removal of organic compounds from inorganic porous surfaces can be performed with organic solvents, even if their toxicity, poor control over cleaning action, and their spread through the porous matrix of the wall make this procedure not advisable. CSGI pioneered the use of nanostructured systems (micellar solutions and microemulsions) for the cleaning of artworks. These systems provide a much safer removal action compared to pure organic solvents and this approach also gives better control over cleaning, and avoids the redeposition of dissolved materials in the pores of the wall. Several innovative gels were also developed, which act as a vehicle for the cleaning agents, and can be loaded with microemulsions or other detergent systems. These gels ensure even more controlled and gradual cleaning action due to their retentive properties. Therefore these systems can be safely used on materials sensitive to water or organic solvents. Current research on nanostructured cleaning media is aimed at the lowering of environmental impact, the reduction of the nonvolatile components amount (i.e. surfactants) and the improvement of the cleaning effectiveness.




Wood and Paper Deacidification

Water-based solutions containing slaked lime are traditionally used for the neutralization of the acidity of paper. The evolution of this methodology is represented by alcohol-based dispersions of alkaline nanoparticles, which can be safely used on water sensitive materials, avoiding the risk of undesired solubilization of inks, sizing or other components. In order to lower the interaction between the dispersing medium and the materials of the manuscript, inert solvents, such as fluorinated, can be used instead of alcohols. CSGI researchers used their know-how about inorganic nanoparticles in order to synthesize tunable systems for the deacidification of both paper and wood. In the case of wood, smaller particles give better results in terms of penetration inside the material. Case studies include conservation of shipwrecks and historical church organ pipes. New formulations specifically designed for the application on cellulose-based works of art are constantly being developed in order to face new conservation challenges.



Cleaning of Easel Paintings

Traditional cleaning of easel paintings involves the use of neat organic solvents. However, their action is poorly controlled and they are likely to cause the undesired solubilization of artwork materials. Classic “solvent gels” represent an alternative to the use of neat solvents, but, in spite of their good cleaning capacity, they may leave residues on the paintings, due to the fact that their network is based on weak physical interactions (“physical” gels).  At CSGI, several innovative gels have been developed: rheoreversible polymeric organogels, which can switch from a solution-type to a gel-type behavior by a simple chemical action; “chemical” gels, which maintain their shape under moderate stresses, allowing their simple and complete removal from the artwork, due to the fact that their network is based on covalent bound; high viscosity polymeric dispersions (HVPD), which possess peculiar rheological behavior and can be peeled off the surface with a minimal mechanical action. All these gels can be loaded with microemulsions (or micellar solutions), or water/solvent mixtures to perform cleaning operations. CSGI researchers are currently working on new systems in the search of finding the optimum balance between rheological/mechanical properties and cleaning effectiveness.



Study and Characterization of Works of Art Materials

Besides the search for innovative conservation methodologies, CSGI also carries out analytical investigations on works of art materials, in order to study their state of conservation and their degradation processes. Several analytical techniques are used for this kind of studies, such as SEM (Scanning Electron Microscopy), FT-IR (Fourier Transform – Infrared Spectroscopy), thermal analyses, optical microscopy and TOF-SIMS (Time of Fligh – Secondary Ion Mass Spectroscopy). Case studies include the analysis of pigments and drawing techniques used by Guercino and Bronzino, the study of the pigments used in the Florentine Codex (a manuscript wrote by a spanish friar in Mexico in XVI century), the characterization of pigments and binders in “the Martyrdom of St. Catherine”, in Zejtun (Malta), the investigation of ancient ceramics from the Quartaia Site, Tuscany (Italy), among the others.



Essential References

  • Baglioni, P. & Giorgi, R. (2006). Soft and hard nanomaterials for restoration and conservation of cultural heritage. SOFT MATTER, 2(4), 293-303.
  • Baglioni, P., Dei, L., Carretti, E. & Giorgi, R. (2009). Gels for the Conservation of Cultural Heritage. LANGMUIR, 25(15), 8373-8374.
  • Baglioni, M., Giorgi, R., Berti, D. & Baglioni, P. (2012). Smart cleaning of cultural heritage: a new challenge for soft nanoscience. NANOSCALE, 4(1), 42-53.
  • Carretti, E., Dei, L. & Baglioni, P. (2003). Solubilization of acrylic and vinyl polymers in nanocontainer solutions. Application of microemulsions and micelles to cultural heritage conservation. LANGMUIR, 19(19), 7867-7872.
  • Carretti, E., Fratini, E., Berti, D., Dei, L. & Baglioni, P. (2009). Nanoscience for Art Conservation: Oil-in-Water Microemulsions Embedded in a Polymeric Network for the Cleaning of Works of Art. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 48(47), 8966-8969.
  • Carretti, E., Bonini, M., Dei, L., Berrie, B. H., Angelova, L. V., Baglioni, P. et al. (2010). New Frontiers in Materials Science for Art Conservation: Responsive Gels and Beyond. ACCOUNTS OF CHEMICAL RESEARCH, 43(6, SI), 751-760.
  • Giorgi, R., Baglioni, M., Berti, D. & Baglioni, P. (2010). New Methodologies for the Conservation of Cultural Heritage: Micellar Solutions, Microemulsions, and Hydroxide Nanoparticles. ACCOUNTS OF CHEMICAL RESEARCH, 43(6, SI), 695-704.
  • Giorgi, R., Chelazzi, D. & Baglioni, P. (2005). Nanoparticles of calcium hydroxide for wood conservation. The deacidification of the Vasa warship. LANGMUIR, 21(23), 10743-10748.
  • Poggi, G., Giorgi, R., Toccafondi, N., Katzur, V. & Baglioni, P. (2010). Hydroxide Nanoparticles for Deacidification and Concomitant Inhibition of Iron-Gall Ink Corrosion of Paper. LANGMUIR, 26(24), 19084-19090.
  • Tognazzi, A., Lapucci, R., Martini, S., Leone, G., Magnani, A. & Rossi, C. (2011). TOF-SIMS characterization of pigments and binders in `the Martyrdom of St. Catherine', in Zejtun (Malta). SURFACE AND INTERFACE ANALYSIS, 43(8, SI), 1152-1159.

 

Clicking on the link below you can download the last CSGI report (2013) containing also studies related to this research area:

CSGI Report 2013
 
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