Fifty Shades of Grey: Cleaning and conservation of David Watson Stevenson’s plaster models

One of the challenges museum conservators  have to face when cleaning historic objects is learning the difference between new dirt, historic dirt, degraded coatings and original surface finishes. All have an effect on the overall appearance of objects and, working with curators, conservators have to decide what needs to be cleaned, removed or kept to preserve the integrity of the object.

A collection of painted plaster models recently received by National Museums Scotland has presented just such a challenge to the Artefact Conservation department.

The National Museums have recently acquired a group of plaster models by Ratho born sculptor David Watson Stevenson (1842-1904). Stevenson is probably best known for his sculpture of William Wallace at the National Wallace Monument in Stirling.

The models have been brought into the conservation labs for condition assessment and treatment before they go on display in a temporary exhibition of new decorative art acquisitions entitled “New For You” in the National Museum of Scotland. They include two models of Robert Burns and a series of models of allegorical females, commissioned for a memorial in Oldham dedicated to John Platt, a Victorian industrialist.

Usually the public get to see objects when we have finished the conservation, however, in this exhibition we will be displaying the  pieces partially cleaned and repaired, to give visitors an insight into what is involved and how the objects will visually change once treatment is completed.

It is always exciting to get new acquisitions, and as a Conservator you get to see these objects at close hand. Sometimes all isn’t as it seems, and once you start working on a piece you start to uncover its secrets. In this case our investigations have led to the conclusion that some of the sculptures would have originally looked very different from how they do today. Using conservation cleaning techniques, we have been able to start restoring the original appearance of some of the sculptures.

Plaster model of Robert Burns
The varnish layer on this plaster model of Robert Burns has aged and degraded, becoming a yellowy green. The varnish layer has been removed to reveal the original white scheme beneath. This is the model of the statue of Burns to be found in Bernard Street, Leith.
Allegorical female figure
Left: Allegorical female being cleaned with dampened cotton swabs to remove surface dirt. Right: The model viewed from above shows the contrast between the clean and dirty surfaces.

We are also starting to understand why some of the sculptures look the way they do now. The allegorical figure on the left has been overpainted. Further investigation shows that the figure was originally painted using copper based metal powders to imitate a bronze finish, giving it an appearance similar to the figure on the right. We  now believe the metal powders on the figure on the left  have corroded and stained the overpaint, causing the darkening to the face and arm.

The figure on the left has been overpainted, to give it a bronze effect finish, similar to the figure on the right
The figure  on the  left has been overpainted. Originally it would have had a bronze effect finish similar to the figure  on the right.

The plaster models have also had to get some first aid treatment. In the past, prominent areas such as toes, fingers and limbs have been damaged by accidental knocks and bumps. Some of the applied paint on the sculptures is now loose and falling off and this has to be stabilised before any cleaning can take place.

Stabilising the fragile painted surface on the bust of Robert Burns.
Stabilising the fragile painted surface on the bust of Robert Burns.

The models also contain iron and copper wire supports called armatures. Due to damp conditions these armatures corrode, the corrosion expands forcing the plaster to spall off the surface and the armatures become weaker. In the worst case this caused the head to detach from the  body  of the figure shown below.

The headless allegorical figure before and during repair
Above: The headless allegorical figure before and during repair with losses to the neck gap filled. Note the corrosion on the head of the figure’s sceptre, which has caused plaster to detach.

You can see the conserved models on display in the Grand Gallery at National Museum of Scotland.

The Stevenson models on display in the Grand Gallery
The Stevenson models on display in the Grand Gallery.

 

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