The painting (264 x 191 cm) is from the State Museum of Medieval and Modern Art, Arezzo.
This work was published in the book: Tecniche avanzate di sottovuoto nel restauro dei dipinti, Edifir-Edizioni Firenze, Firenze, 2007.
The painting was in a very poor state of preservation, with widespread lifting and delamination of the paint and ground layers.
The impregnation of heated natural consolidant (glue) was divided into four phases, each involving one-quarter of the surface of the panel, for better control of the impregnation processes and to reduce the time of exposure to the moisture.
The panel was inserted into the envelope, sealed with plasticine and gradually subjected to vacuum pressure. Hot glue was then injected the through the nylon of the envelope. The operator was guided by the diffusion of the liquid in the Japanese paper protecting the paint film, showing the extent of the treated area.
The applications were repeated for several days and ceased with complete desorption of the aqueous component of the consolidant from the ground layer.
The results of the sectorial vacuum consolidation were even beyond our expectations. In practice, the delaminations and crests of paint returned to their place on the surface of the painting, leaving intact all the large and small brushwork peaks and very small lumps of paint; at the same time, the gesso and glue ground layers were perfectly reconsolidated.
Whole painting, before vacuum consolidation of the paint film.
Detail in raking light before vacuum consolidation of the paint film.
The photographs show the numerous delaminations of the surface of the painting.
Preparation of the envelope and the panel.
The panel was placed in the envelope, sealed with plasticine and gradually subjected to vacuum pressure.
Injection above the Japanese paper during general vacuum consolidation.
The envelope was divided into four equal rectangles and marked with adhesive tape; the Japanese paper was placed beyond the marked limits, although the limits were respected during consolidant impregnation. As the glue moistened the Japanese paper, it indicated the extent of the treated area.
Detail in raking light (the light originates from the right for technical reasons) of the lower right angle of the painting before consolidation of the paint surface; the image shows the numerous delaminations of the paint distributed along the fibres of the wood.
Detail in raking light (the light originates from the right for technical reasons) after vacuum consolidation of the paint film; the delaminations have disappeared and only a crack where the wood pieces meet is evident.
Detail in raking light (the light originates from right) of the face of the Madonna. The still unconsolidated zone (A) shows numerous delaminations of the paint film. Zone B has been vacuum consolidated; the broken line indicates the boundary between the two parts; the whiteness of this zone is caused by residues (down) of the Japanese paper highlighted by the raking light, which were removed in the cleaning phase.
Detail in raking light (the light originates from right) of the face of the Madonna after the entire surface of the painting has been consolidated. The photograph was taken several days after the end of vacuum consolidation; the delaminations have disappeared after perfect re-adhesion to the support.
Madonna after restoration.
