Conservation of the Cruciform Hub’s Historical Busts

By Emma Prideaux and Cyril Maucourant

Following the introduction of the busts (Here!), we explain the conservation process. The process involved four main steps: observation, investigation, deliberation and treatment.


Students need to work out what needs to be done to these objects before a plan of action can be drawn up. So each statue will be first examined thoroughly and these observations will be recorded, through written descriptions, photographs and illustrations. These records also function as a record of what the object was like before treatment. Observation can be simply viewing the object with the naked eye, but magnified lenses or digital microscope using visible light, IR and UV, can be used to observe specific details related to decay mechanisms or highlight traces of materials from past conservation treatments (Fig. 1.) .

Dowel pins detail

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Figure 1. Recording evidence of dry corrosion on a tip of a dowel pin (Maucourant, 2016)


This stage is essential to determine the chemical nature of materials the object is made of. This can inform us of the correct chemicals needed to instigate conservation work.

This can be as simple as removing a sample of adhesive from the surface of the object, placing it on a clear slide and dropping acetone on it, to see if it will dissolve. More intensive analysis, usually involves equipment such as a pXrf or a Scanning Electron Microscope, which can be used to provide information about the surface morphology and micro-crystalline matrix. With this information, a critical analysis about the choice of materials used for conservation treatment can be proposed.

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Figure 2. Location of two different accretions in the surface of the bust (Wang, 2016)


When the conservators have decided what is feasible, the next step is to consult with the ‘stakeholders’. In this case, those in charge of the marble busts, and each other. This is to ensure that the conservation work aligns with the goals of the owners of the object.

The fact that these marble busts are part of a set can complicates matters. This group of objects will all be displayed together. The conservators must consult each other to ensure that all the marble busts and both the plaster busts retain the same aesthetic after conservation.

Once a conservation treatment has been formally agreed, the students can then move onto conservation treatment of the objects.

Cleaning tests back of bust results

Figure 3. Testing cleaning methods – results (Maucourant, 2016)

Conservation treatment

Finally, after observation, investigation, and deliberation these objects can begin to be treated.

Conservation is, at its heart, problem solving, and each statue will provide its own challenges and solutions. This can be as simple as brushing the dust off the surface of the object, to reconstructing missing fragments of stone. A range of tools can be used, from bamboo sticks and cotton wool to scalpels and Plaster of Paris fills. The techniques used on this object set will vary widely – some of the statues are plaster, some are marble. Some objects need to have aesthetic repairs whilst others need structural repairs.


Figure 4. Some need significant repairs (De la Serna, 2016)


More on the treatment soon!



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