Past & Present Work

Project:The Altar of St Roc.
Client: The Croatian Restoration Institute
Head Conservator: Romana Jagic
Date: 2001

History
The Altar of Saint Roc is found in a side Chapel at The Church of The Three Kings, in Komin, approx 50km Northeast of Zagreb, Croatia. St Roc was a hermit born in Montpelier in 1350, who was reputed to have cured and protected people from the plague.

The Altar, dated 1780, is attributed to Weinachta, a well-known Altar painter of the time. It came to the attention of the Croatian Restoration Institute in May 2001. It seems that it had been forgotten and neglected over the years and was found covered behind boards and furniture. The conditions in the Chapel had been unfavourable for some time. A leaking roof had caused serious damp problems to the fabric of the chapel and had caused lifting oil paint flakes, deteriorated gesso, unstable gilding, wooden substrate, fluctuating humidity, animal glue, traces of original paint layers (azurite).

Description of the Altar:
The Altar is constructed of pine, with the decorative carvings in lime. A polychrome and gilt surface surrounds the central canvas painting of St Roc. The Altar is composed of seven pieces; the Predella, the painting and frame, the Retable with two Altar wings, the Capitals and the Attica.

Dimensions
Altar height 186cm
Altar width 190cm
Alter depth 32 cm

On site evaluation
The overall condition of the object was very poor; the paint on the wood had deteriorated badly due to the movement of the wooden substrate. The Gesso layer underneath the paint had lost its strength and was very dry and crumbly. The whole object was in need of consolidation to stop any further loss of the polychromy. Due to the dampness within the chapel and the poor condition of the walls, the Altar was suffering from rot. Extensive signs of insect damage were apparent, the fresh exit holes and fine powder suggested recent activity of woodworm.

Missing elements: Two statues believed to have been St Florian and St Sebastian.

On site cleaning:
The chapel in which the Altar was housed, was used more or less as a storeroom. This was re-organised so that we were able to work in a safe and clean environment. Superficial cleaning of the Altar was carefully carried out with soft brushes, to allow for closer examination and primary consolidation.

On site consolidation:
It was necessary to pre-consolidate the Altar in situ, in order for it to be stable enough to transport to the workshop. The surfaces and gesso layers were extremely dry and fragile. We decided to use rabbit skin glue at a ratio of 1:14 and a vehicle of 50:50 ethanol and de-ionised water. A few applications of the glue were necessary to hold the polychromy in place. The glue was applied through a syringe, allowing us to inject into fine cracks. At this point, we did not attempt to flatten or re-locate any paint layers, only to hold them in place.

Dismantling of Altar:
After the Altar was photographed, investigations into its construction were carried out. It became apparent that many of the Altars fixings, both into the wall and between different sections, were suffering from nail fatigue and many were redundant. The sections dismantled easily from one another and any remaining nails were sawn free. Each section was carefully packed and photographed again. Once packed, a decision was made to transport the sections in an air-conditioned vehicle, so that the humidity could be controlled.

Conservation in the workshop:
The objects were carefully unpacked and lightly cleaned using a vacuum with muslin over the nozzle, to prevent loss of the original surface. The painted and gilded surfaces were still very vulnerable, and many applications of the consolidant (rabbit skin glue and de-ionised water 1:14 and a vehicle of ethanol and water at a 50-50%) were necessary, because the gesso layer was so dry.

Flattening the paint layers.
The paint layers were insoluble in water and reasonably thick, so the binding medium was oil based. Over the years, the paint had cracked and dried, causing the layers to curl up and in some cases fall off. However, eighty percent still remained, of which about a further twenty five percent was in a critical condition.

To flatten the layers, I first had to re-hydrate the gesso underneath and allow them to soften gently, this required many local applications. Once the layers were soft enough to manipulate, I injected glue under the surface. In some cases, the gesso was lost or very thin, so that it meant attaching the paint layer to the wooden substrate. Once the layer was in the correct location, I ironed the area with a small shoe soldering iron, using cigarette papers as an isolating layer. It was important to dry the paper thoroughly and leave it until the area was cold to the touch before removing it. Once the glue had cured, the paper could be removed using a damp swab.

Cleaning:
For the cleaning of the painted surface, spot tests were carried out to ascertain which solvent or cleaning agent would be appropriate. Results showed that warm de-ionised water had the best affect, although in areas of extensive consolidation it had a tendency to reactivate the rabbit skin glue. To lessen this reaction a mixture of 50:50 ethanol and de-ionised water was used.

For the cleaning of the gilded surface, again spot tests were done. It was clear that ethanol and water were again the most effective at removing the dirt, although it was important to be very careful so as not to loose any of the gold.

Conclusion
All components of the Altar are now stable and eventually it is hoped that the object will be reinstated in its original position, as it is still venerated by the local population.

Lifting paint flake

Paint flake re-adhered and consolidated

Studio at Ludbreg, Croatia

Cleaning tests on gilded wood