The Light of the Last Judgement

Written by  Ottorino Nonfarmale
The restoration of the paintings in the apsidal semi-dome of Ferrara Cathedral.
The complex task of restoring the paintings in the apsidal semi-dome began with an analysis of the materials. The results of the lab analyses were assessed in concomitance with information culled from historical documents. It was not clear how Bastianino had worked using the a secco method described in the contract; in fact, the areas where the colour had lifted were areas painted using a diluted oil finish.

In the course of a restoration made in 1748, the restorers deduced that the entire painting had been executed in oil. The damage suffered by the painting sprang from this erroneous interpretation. Furthermore, this damage was aggravated by water seepage from the roof that, in various areas, caused oxidization and fading.

The deductions made by Boari, who carried out the work done in 1852, are that Bastianino's contract with the Curia called for the fresco to be painted a secco.
In fact Bastianino had executed his painting by sketching in everything a fresco using tempera, gouache, and highly diluted linseed oil, as confirmed by the lab analyses. Today this technique would be described simply as a mixed method. In the past, in the course of restoration work, cleaning was carried out always and only on the surface.

After the cleaning tests, the comparisons, and the definitive presentation of the results to the persons in charge of the project, we were given the green light and the real work of restoration commenced.
Cleaning proved to be a very demanding and delicate task, owing to the widely differing original materials and to certain complications that arose as a consequence of previous cleaning operations that had never quite eliminated either superficial or underlying traces of bitumen.

With the aid of compresses impregnated with solvents and extracting agents we managed to solve much of this problem. After cleaning, which did away with the many previous restorations as well as the bitumen, the limpid clarity of images concealed for centuries emerged anew.
After a reading of the documents, and after having checked out and thought over the results of the analyses of the samples taken from the painting, we proceeded to the observation of the painting using frontal and oblique light, and to an analysis using ultraviolet and infrared equipment.

As far as concerns the alteration of the materials due to external agencies, seepage, and old restorations, our methodology - tested at various points in order to assess the results, which were then checked against the reports on the samples and the old documents - afforded us a clear grasp of the complexities of the state of alteration and decay affecting the entire painted surface. One could also say frescoed surface: because in point of fact so much a secco work had been lost in the course of previous restorations that most of what remained was Bastianino's original work, which was executed a fresco.
The next step was consolidation and cleaning sector by sector.
The presence of tempera a secco work made the operation a very tricky one. But the compresses, made of sheets of very thick paper, caused the retouched areas to bloat and this made it possible for us to extract both superficial and underlying bitumen.

Where we found tempera, we used only water, dabbing at the compress and adding a solvent to aid in the extraction of the bitumen only towards the end of the process. When the surface was almost dry it was possible to locate repainted areas, always using small damp sponges, spatulas tipped with cotton wads, or small paintbrushes. After having identified these areas, thanks to these precautions it was possible to eliminate small residues and to recover the original colours beneath.

In the top right area there is a final finishing coat of plaster where the painter began to paint a fresco: this area was badly cracked and had come away from the plaster undercoat. We consolidated the plaster by injecting an acrylic resin emulsion, protecting the fresco beforehand with a protective layer of small sheets of Japanese paper.
Bastianino's very rapid, impressionistic style was, however, technically not too well suited to a fresco painting. I think that someone probably suggested this mixed method to Bastianino because he was insufficiently well versed in the complex and difficult fresco techniques. The identities of the restorers who made mistakes and damaged the fresco will never be known: the problem is that Bastianino's execution has consistently been misinterpreted.

In the course of our work, we found traces of tempera work that had been removed, one particularly evident example being one of the angels or nudes that stand above God the Father in the vault; in all probability this is probably a case of a pentimento that had been partly eliminated, leaving on the frescoed flesh traces of this old pentimento, subsequently painted over.

We removed the repainted areas and all remaining traces of the pentimento. In this way we recovered the original frescoed nude, leaving intact those traces of the pentimento still extant (an arm and a part of the face), which were painted outside this figure, above the sky, and which do not disturb the dense composition of characters.
The sky still retained traces of the original cherubim. All, or almost all, of the sky had been painted over with a thick coat of tempera in order to conceal seams and areas with losses.
By working selectively in the manner explained above it was possible to recover what original work remained.
In the inventory made on 16 July 1766 we find that a certain Lazzari, a housepainter, was employed to whitewash the choir and to clean away the dust and cobwebs from the Last Judgement above it.
In all probability this task was carried out using a ladder and long poles with dusters attached, an operation that caused evident horizontal scratches and the dislodgement of small areas of plaster.

All this mechanical damage was visible after cleaning and before repainting. Upon the completion of the cleaning process and the injections required to bind the plaster that had come away, the final cleaning of many areas of the paintings was effected using distilled water. The task of consolidation was carried out by applying stucco to the scratched areas, to the cracks, and to the great number of holes in the surface. On the right hand side of the vault some figurative work has been lost owing to water seepage. Two cracks caused by settling were filled first with sand and lime, before finishing with additional powdered limestone.

The painting work was carried out according to a criterion based on chromatic selection and was executed in tempera where it was necessary to cover, while a thin coat of watercolour was applied to the abraded areas.