Past and present treatment: Bronze statuette of Thutmose IV
The colour of this statuette is striking. It is a vivid mixture of red and green. This is not its original appearance, nor is it the way it looked when it was excavated. The colour is that of corrosion products which formed on the metal while it was buried. When it was first made and used, this statuette would have had a smooth surface. If the colour changed at all, it would have been a slow darkening or tarnishing. Buried in the ground, the red corrosion product copper oxide gradually formed on the surface, then the green copper carbonate. These can form quite thick, rough layers. The appearance we see here is the result of an early restorer's efforts to smooth the surface down and show up details. Chemicals may have been used to partly strip away corrosion, as was often done in the past. The statuette was certainly filed and rubbed, as can be seen from the marks left on the surface. The result was this multi-coloured and slightly blurred finish.
But no matter what the restorer did, the original condition of the statuette could not be 'restored'. This is never possible. What the modern conservator tries to do is slow down the processes of change until they are imperceptible. If he or she changes the object at all, it will be in order to help preserve it or to discover the information locked up in it. For instance, what was the original appearance of this statuette? Was it all the bright golden colour of bronze? Or did the ancient Egyptians want their statues to be as colourful as their paintings and mummy-cases? Research going on in The British Museum's Departments of Conservation and Scientific Research is exploring these questions. Careful examination and investigative cleaning under the microscope allows the conservator to identify the evidence. Scientific analysis tells us exactly what we are dealing with.