A Honey Pot for Springtime!
By Susi Pancaldo, on 31 March 2016
As a Conservator, I often think of how privileged I am to be able to handle and examine museum objects, up close and personal. Not all objects move me, but at the moment I am very pleased to be working on this one:
This ceramic bowl was probably made in Upper (southern) Egypt in the late Ptolemaic or Roman Period; that is, in the centuries just before or after the beginning of the Common Era (0 BC). The delicate vessel was made on a slow potter’s wheel from a fine-grained, pink clay. After drying, it was was painted with a thin red clay layer (‘slip’). Lastly, a scene of busy bees, in flight amongst honey combs, was painted using a host of colours: shades of black, red, yellow and white.
Who made the bowl, who used it and what it was used for in ancient times, we do not know for sure. We do know that the vessel was archaeologically deposited at some point, and then excavated, probably around the turn of the 20th century AD. The bowl made its way to the UK and into the Petrie Museum, probably from one of Sir Wm M F Petrie’s excavations – at Koptos, for example, or Qasr Ibrim in Nubia, both sites where this type of pottery has been found. Alternatively, the vessel may have come to the museum in the late 1960s, via the Henry Wellcome Trust. Research in the museum’s archives would likely reveal which.
Whatever the source, it is clear that the vessel has been broken and repaired at least twice since it was excavated. This was revealed when the bowl was examined under ultra-violet light:
In visible light, adhesive along the break edges (and in some areas smeared on the surface) appears grimy and yellowed from age. It was only when I looked at the fragment joins under UV radiation that two different resins were detected.
Examination under UV radiation (wearing safety goggles to protect the eyes!) is a handy trick which takes advantage of the fact that some materials, when exposed UV, will fluoresce – that is, they emit light radiation which can be detected by the human eye. If a distinct colour is emitted – such as bright orange, or the eerie light green seen in the images above right – an educated guess can be made about the identity of the substance. From experience, I can be fairly confident that the orange-fluorescent substance seen in the right-hand images above is shellac, and the green-fluorescent substance is cellulose nitrate. Both these materials were commonly used in the past to repair archaeological ceramics.
Now that I have an idea of the identity of the resins used on the vessel, I can carry out further tests for confirmation. It is important to confirm as precisely as possible what conservation materials were used — in part to inform treatment decisions, but also because identification of the adhesives will contribute to an understanding of the post-excavation history of the object and the field of archaeological conservation. Further tests will include examining the solubility of the resins using various organic solvents, and conducting Fourier transform infrared spectroscopy (FTIR) analysis.
Then, finally, the vessel can be repaired, for a third time! I will first remove as much of the old, aged resins as possible from surfaces of the pottery fragments. I will then readhere the fragments using a modern conservation adhesive. The bowl will then be ready for redisplay – what a way to celebrate Spring!!
Susi Pancaldo is Senior Conservator, UCL PACE Museums and Collections