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Ortolano. An Altarpiece of Poplar Wood

Conservation is a complex and resource demanding process. Read about the work on the conservation of the altarpiece Saint Margaret.

Saint Margaret

The painting of Saint Margaret, dated 1524, was originally an altarpiece in one of the churches in the North Italian town, Ferrara. It was painted by Giovanni Battista Benvenuti, also called l’Ortolano (1487-1527).

Altarpiece of poplar wood
The altarpiece was painted on a panel of poplar wood. Poplar wood was the preferred support for paintings in Italy at the time, in cases where the painter chose not to paint on canvas. The poplar panel was made from three vertical planks held together by wooden dowels and butterfly inserts. Originally the panel had a thickness of about an inch.

Insect damage
At some point however, perhaps even before the painting came to Denmark in 1763, the panel was planed down to a thickness of just 1 cm. It probably happened in order to tackle the extensive insect damage but very likely also to keep the panel flat. Because at the same time, thick mahogany planks were glued on horizontally, covering the entire reverse of the panel.

Harmful mahogany
In time the mahogany planks turned out to have an unfortunate effect on the painting, making it warp in the vertical direction. And the deformation caused by the glued-on individual planks could also be seen on the front of the painting. The forces within the mahogany were in fact so strong that in various places they threatened to pull apart the original panel.

It was therefore decided to remove the harmful mahogany and replace it with a more suitable device which could support the fragile and reactive poplar panel but without restraining it unduly from moving in response to small variations in the surrounding climate.

Deep grooves were cut lengthwise and crosswise in the mahogany, whereupon the resulting small squares could be removed individually with a chisel. Finally the remaining veneer-thin layer of mahogany and glue was scraped off after being humidified.

Click on the fotos for enlargements

Tom Egelund cuts deep grooves in the mahogany

The grooves

Tom Egelund removes the mahogany

Support by sitka spruce
After the removal of the mahogany a series of recordings monitored the response of the original poplar panel to changes in the relative humidity. The results were utilized in the construction of a new auxiliary support attached to the back of the panel. Horizontal and vertical, flexible battens made of sitka spruce are placed in grooves in small blocks of poplar wood which have been glued onto the panel. Apart from that the system can be easily removed in a very short time, a particular feature is its flexibility. It strengthens the panel and modifies its warping but at the same time does not block entirely its natural tendency to moving in response to variations in the surrounding climate. The poplar panel is now secured.

The design, construction and fitting of the support was carried out by Ray Marchant, Simon Bobak's Studio London. The work was attended by Sue Ann Chui, conservator at The J. Paul Getty Museum in Los Angeles.

Cleaning and restoration
However, before the altarpiece goes back on view in the Gallery, Troels Filtenborg will carry out cleaning and restoration of the paint layer.

The Saint Margaret by Ortolano is a good example of a complex and resource demanding conservation treatment.

Written by
Troels Filtenborg
Senior Conservator, paintings
Conservation Department

Read more about Troels Filtenborg

Read more about the conservation of works of Unique National Importance made possible due to a special appropriation from the Ministry of Culture.

Updated: 29.apr.2015
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