Poster 6 – extended abstract

The recreation of the Rijksmuseum sculpture garden within the Amsterdam cityscape

Nicolas Diane Walter Verhulst, Alfred Wilgenburg, Isabelle Garachon and Frits Scholten

Click here to view the poster in PDF.

After years of delay the Rijksmuseum in Amsterdam (NL) opened its doors again to the general public in April 2013. Not only does the building, dating from 1876–1885 and designed by Pierre Cypers (1827–1921), house an important art collection, but the general public can also freely enjoy the sculptures and historic fragments surrounding this cathedral to art. With the recent completion of the restoration of the Philips wing, this part of the garden too opened for the public in April 2015.

The collection has grown over time, instigating a change in how it should be displayed. The garden is no exception. It was originally divided into specific styles (French, English, etc.), with different types of objects being displayed together. The museum collection contains sculptures as well as building fragments from all over the Netherlands, and plays a crucial part in the way visitors experience historic Dutch building styles. Many of these fragments have since disappeared from the garden, due to changing tastes over the last century. The recent renovation of the museum has allowed for a new approach regarding the display of the remaining objects, and the re-installation of objects that had been moved to the storage. New additions of an interactive fountain, a coffee house within a historic pavilion and a centrepiece chessboard help to create an enjoyable atmosphere in which to enjoy the outdoor masterpieces.

All the chosen objects, including the 128 reliefs in the façade, two historic garden pavilions, an entrance gate, former city gates and a modern telephone booth, were documented before conservation and restoration strategies were discussed. The objects and their plinths contain a wide range of materials: marble (6), sandstone (24), limestone (3), ceramics (1), lead (4), bronze (3). Every case presented ethical dilemmas concerning their aesthetic representation, and how to deal with former treatments. New treatments included moving an 18th century historic garden pavilion, cleaning, mortar repairs, repointing, retouching as a protective coating, wax treatments. Technical research concerning surface deterioration of limestone was executed. Material analyses of a sandstone consolidation treatment from the 1980s was compared to condition reports, giving an insight into the deterioration of the object over time.

Some of the case highlights will be briefly discussed here:

A terracotta garden bench: (‘De Visser’ – BK-1972-88) was placed underneath a pergola. Cement joints were causing damage and were replaced with a commercial hydraulic lime mortar. Texture and colour were important to watch out for. Now this place has become a perfect hiding spot for people, which entails problems of its own for the object.

Two Roman emperors, white marble Carrara busts, had a weathered surface – not sugaring however. Biological growth was abundant and left black disturbing spots in between the marble crystals. To achieve a more homogenous image it was decided to bleach the surface. These two busts stand at the corner of a long hedge and are placed on new plinths of Portuguese marble. A stainless steel rod from the plinth in the busts prevents the sculptures from falling if they are pushed. Similar fixings were executed for the other objects.

In the same hedge four sandstone (Obernkirchner) sculptures by Ignatius van Loghteren (1685–1732) and Jan van Logtheren (1709–1745) stand on their original plinths. The typical local black appearance that sandstone gets over time was reduced slightly with the help of micro sand blasting at low pressure and volume to reduce the impact. The lighter weathered parts were locally treated with a lime paste and a low percentage of PVAc-based glue to achieve a better adhesion. The bigger missing parts were treated with a lime-based commercial mortar. For an overall more homogenous appearance the sculptures were treated with paint based on ethyl silicate. The paint was sprayed as a thin mask over the disturbing parts.

Besides these sculptures, Ignatius van Loghteren created a garden pavilion. The whole of the top had become detached because of the use of wooden pegs. After disassembly, fixing was possible with stainless steel and chemical anchors. A new marble sundial replaced one that had been badly damaged. Before the coffee house, a new interactive fountain plays an important role in the liveliness of this part of the garden.

The position of another corner pavilion did not work anymore, as it blocked restaurant visitors’ view from the Museum Square. It was decided to dismantle the sandstone fragments and cut the surrounding brick walls in four pieces after taking off the roof. At the opposite side of the Philips wing it was rebuilt in front of the central chessboard.

Around the chessboard four marble vases with marble covers and their sandstone plinths were cleaned with water, brushes and sponges, after which they were treated with a biocide. Like the two marble busts, the weathered covers were treated with a protective coating, which also acts as a biocide.

Three big columns from a church were badly weathered. Already, centimetres of the surface had been lost, but after investigation (DRMS) it became clear this weathering was superficial. Another problem was the foundation of one of the columns, which was sinking, one of the arches showing worrying cracks. The foundation was partially rebuilt, the cracks were injected and the missing parts of sandy limestone columns repointed (previously, they had been partially covered with a an excessively hard mortar).

The main challenge with the city gates was to obtain a representative historic gate. Because the gates were not complete, additions were made in the past in cement (sometimes up to around 80%). These were disturbing and were patinated to fit the surrounding stone.

Four large sandstone sculptures by Jan Pieter van Baurscheit the elder (1669–1728) were cleaned heavily in the 1980s with chemicals (Neolith HDL) and consolidated with Motema – steinfestiger 28 S. Analyses of samples by SEM-EDX, XRD and GC-MS confirmed this silicate treatment and gave also insight that a sand-epoxy based resin mortar with titanium white was used in previous restoration. These additions became very disturbing to the biologically contaminated surrounding surface. After cleaning the statues, local mortar gap filling and patination with paint sprayers, the statues went back in the garden on Belgian blue limestone plinths.

A sandstone statue by Rombout Verhulst (1624–1698) locally lost its stone surface. The original black surface now contrasted badly with the eroded parts. By patinating these lighter parts darker, it was possible visually to create a not disturbing appearance without filling all the gaps with a coloured mortar.

Since the reopening of the Rijksmuseum, the garden has become a green hotspot, the number of visitors presenting its own challenges in terms of the preventive conservation measures to be taken in conjunction with the Dutch climatic conditions.