Press Release
Feb. 25, 2009
Non-invasive Observation of Internal Structure of a Giotto's Masterpiece by THz Imaging
－The modern figure on the medieval preparation is revealved －
National Institute of Information and Communications Technology (Tokyo, Japan) have applied THz imaging to the analysis of a Giotto's masterpiece, "Polittico di Badia" (c.a. 1300) at the Uffizi Gallery (Florence, Italy), as a collaborative work with the Istituto di Fisica Applicata "Nero Carrara"-Consiglio Nazionale delle Ricerche (Florence, Italy). This is the first ever internal observation of a tempera masterpiece with maps of the layer of interest, and was introduced in a newsletter of International Institute for Conservation of Historic and Artistic Works, "News in Conservation", February issue.
The non-destructive cross section image clearly shows the layer structure which contains a base of wood, a gypsum layer for smoothing wooden surfaces, a cloth, a preparation gypsum, and finally painting layer, It proves that Giotto followed the early Renaissance polyptychs manner for the preparation.
This three dimensional non-invasive observation of paintings cannot be realised by conventional method. The findings should attract art historians interests and can give practical information to conservators.
[Technology used in this work]
Terahertz (THz) rays can penetrate opaque materials, and can analyse multi-layer objects. Its time domain spectroscopy and tomography has been used to interrogate tablets of medicine and THz imaging has been also applied to various security issues. T-rayTM4000 of Picometrix (Michigan, USA) was used for this experiments, and data was analysed based on the spectral database developed by NICT.
Terahertz (THz) rays can penetrate opaque materials, and can analyse multi-layer objects. Its time domain spectroscopy and tomography has been used to interrogate tablets of medicine and THz imaging has been also applied to various security issues. T-rayTM4000 of Picometrix (Michigan, USA) was used for this experiments, and data was analysed based on the spectral database developed by NICT.
[Future work]
This tempera polyptych "Polittico di Badia" had been under restoration by Stefano Scarpelli in the Uffizi Gallery in Florence, and will be at the exhibition "Giotto e il Trecento" in Rome from 6 March. A catalogue of the restoration activities with additional scientific analysis results will be published in the future.
This tempera polyptych "Polittico di Badia" had been under restoration by Stefano Scarpelli in the Uffizi Gallery in Florence, and will be at the exhibition "Giotto e il Trecento" in Rome from 6 March. A catalogue of the restoration activities with additional scientific analysis results will be published in the future.
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Electromagnetic Research Center
Kaori Fukunaga
Tel ：+81 42 327 6259
Fax ：+81 42 327 6673
Electromagnetic Research Center
Kaori Fukunaga
Tel ：+81 42 327 6259
Fax ：+81 42 327 6673
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Sachiko Hirota
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Strategic Planning Department
Public Relations Office
Sachiko Hirota
Tel ：+81-42-327-6923
Fax：+81 42 327 7587
[Example of results]
The strength of reflection is displayed as gray scale, highest as white and the lowest as black in the following figures. THz reflection image of he area (a) revealed several interesting features. Since the reflection from the gold is strong, existence of gold foil under paints is clearly observed at the outline of the head of Christ. The non-destructive cross section image shown in the figure was obtained along the line labelled (b). The layered structure of the painting can be clearly seen, with the area mapping. The base wood has uneven surface, because it was carved from thicker wood panel to make the painting panel and its frame, and the bottom gypsum layer looked as if it flattened the wood base. A cloth was placed on the gypsum while it is placed directly on a base wood in modern tempera paintings. A gypsum layer was prepared for painting on the cloth.
We thank Uffizi Gallery for the access to "Polittico di Badia", and the use of images.
The strength of reflection is displayed as gray scale, highest as white and the lowest as black in the following figures. THz reflection image of he area (a) revealed several interesting features. Since the reflection from the gold is strong, existence of gold foil under paints is clearly observed at the outline of the head of Christ. The non-destructive cross section image shown in the figure was obtained along the line labelled (b). The layered structure of the painting can be clearly seen, with the area mapping. The base wood has uneven surface, because it was carved from thicker wood panel to make the painting panel and its frame, and the bottom gypsum layer looked as if it flattened the wood base. A cloth was placed on the gypsum while it is placed directly on a base wood in modern tempera paintings. A gypsum layer was prepared for painting on the cloth.
We thank Uffizi Gallery for the access to "Polittico di Badia", and the use of images.
