Sint-Martinus church, Aalst
Reason: restoration of the sacrament house
The start of the restoration works on the Sint-Martinus church in Aalst could not miss out on the treatment of the eight metres high, richly decorated Sacrament House. The monument, which dates from 1604, consists of three towers and is decorated with a hundred sculptures. The imposing work is by Hieronymus Du Quesnoy the Elder, court sculptor to the Archdukes Albert VII of Austria and Isabella of Spain and creator of Manneken Pis. The monument is a Eucharistic Tower, the place where the consecrated wafers are still kept.
The stone sculpture studio of the KIK was asked to give the tower, which consists of valuable natural stone (marble, alabaster) and painted stone sculptures, a conservation treatment. First, a cleaning protocol was drawn up that was tailored to all the different materials. Then the monumental work of art was cleaned, broken pieces were glued together and it was restored to its harmonious appearance thanks to retouches.
Because the polychromy had hardly been studied during the preliminary investigation, the KIK was given the green light to study it in greater depth. Some 30 cross-sections of the successive layers of paint on the various parts of the tower proved to bear no resemblance to each other: the oldest original layer had a different grey value on each sample. And this while it was assumed that the statues had always been painted monochrome white! It was then that conservator-restorer Camille De Clercq, who specialises in the study of polychromy on stone sculptures, set to work with scalpel and loupe glasses. She made a number of stratigraphic windows and carefully removed the white overpaintings from a number of statues. Thus, the original polychromy became visible again and its quality could be thoroughly evaluated.
What emerged was that beneath the numerous layers of white paint, the limestone statues and architectural components were painted in a semi-grisaille technique. Originally the alabaster reliefs between the different floors of the sacrament house were not painted. After all, alabaster, like marble, was considered a noble material. However, the reliefs were partly gilded with gold leaf to create light accents.
A unique semi-grisaille
In grisaille, a painter uses many shades of grey to accentuate shapes with subtle shading. Because only colour accents have been applied to the skin parts, lips, cheeks and eyes on the Aalstres sacrament tower, we speak here of a semi-grisaille. The fine oil painting was applied directly, without preparation, to the limestone.
Since the 14th century, semi-grisaille has often been used on stained glass windows, miniatures, murals and paintings on canvas and panel, but the application of the technique to sculpture has never been demonstrated. In sculpture, the technique is not expected because the 3d models create a natural play of light and shadow. In Aalst, the semi-grisaille gives the natural light effect extra depth so that even the smaller sculptures on the upper tower floors are perfectly legible. This refined grisaille polychromy is absolutely unique. Moreover, church accounts have identified the artist: the hitherto unknown painter Jan Van Benthem.
Uncovering with scalpel and magnifying glass
Uncovering the original painting is very time-consuming. The best way to uncover them without damage is with a fine scalpel and loupe glasses (x10 magnification). Such an operation can only be carried out by experienced restorers specialising in polychromed stone sculpture, and would take many years. Therefore, in consultation with the church council, KIK decided to only uncover the area around the sacrarium on the south side. This way, the viewer can still get an idea of what the building once looked like.