INTRODUCTION
The mural Painting of the dome (diameter 4.92 m) portrays angels in glory, arranged in a concentric and almost modular sequence. The painting was carried out, as the inscription indicates, by Galileo Chini in 1911, using a pictorial technique with proteinous tempera ( dry) characteristic of the Chinian workshop, and in particular of Galileo.
STATE OF PRESERVATION
The use of painting with tempera on the outside was subject, to a greater extent, to deterioration, which may have been caused by various factors ( salty infiltrations, atmospheric humidity etc.) A characteristic deterioration of dry painting, in particular the Chinian type ( as we have had means of verifying in other experiences) was the almost total powdery quality of the pictorial film due to the weakening of the proteinous tempera (binder of the pigments).
The painting turned out to be slightly darkened because of the solid particles of the deposit (dust, soot etc.); furthermore, one could note three principal areas of deterioration caused by infiltrations of water, where there was loss of colour and raised flaking. Small losses of colour could be detected in several areas.
The boundary of the painting was marked at the bottom by a band composed of two smooth conical stones in a light colour alternated to a band painted as false red marble.
The stone background of the underlying bay was natural, in a warm tone, even though traces of artificial coating could be observed.
INTERVENTIONS OF THE RESTORATION
- Pictorial surface : approx. 46 sq. m
- Smooth frames : approx. 9 sq. m
- Stone surfaces : approx. 35 sq. m
► Preventive fastening, where considered necessary, of fragments or portions of unstable plaster with the aim of permitting subsequent operations.
► Pre-consolidation of micro and macro raising of colour, fixing of the powdery areas through injections of 3% acrylic resin and subsequent padding with natural sponges, with the intervention of Japanese paper.
► Cleaning of the whole pictorial surface: first removal of solid superficial particles using small flat brushes and micro aspirators. Subsequent more accurate cleaning carried out in a dry manner with special Wishab sponges, used in the presence of more compact stains and efflorescences, compresses of two layers of Japanese paper spread with de-ionized water and/or a solution of ammonia bicarbonate.
► Compresses of saline absorbers where considered necessary.
► Cleaning of the parts in gold using a solution with a base of water, alcohol and ammonium hydrate.
► Reinforcing of the plaster carried out with injections of specific mortar and de-salted PLM-AL and subsequent propping of the area of intervention.
► Filling of the cracks and defects with mortar with a lime ( slaked lime) and sand base.
► Pictorial integration of the abrasions and defects through veiling and tonal reduction using stable mineral pigments.
► The real necessity for a final superficial reinforcing to restore cohesion to the pictorial film had to be evaluated.
