In summer 2012 the Vorderasiatisches Museum’s conservation department took up permanent residency in three, purpose-built conservation studios for stone, ceramics/organic materials, and metal, installed at the Staatliche Museen’s new Archäologisches Zentrum and situated in close proximity to the collection’s exhibitions at the Pergamonmuseum, as well as the storerooms for archaeological objects and clay tablets bearing cuneiform script. These state-of-the-art facilities and the wealth of experience of our conservators (who are world-renowned in their field) provide the ideal conditions for the collections care, scientific analysis of individual objects, and the development of new conservation and restoration methodologies. All our conservator-restorers are involved in research and teaching. Thanks to their knowledge and their experience they receive increasing numbers of requests to assist in national and international projects.
The stone objects in the Vorderasiatisches Museum’s collection are subject to various degradation processes, most of which issue from the circumstances surrounding the archaeological finds. Some treatments, however, are necessary as a result of much more recent damage caused by the effects of war and inappropriate restoration actions. In addition to restoration and conservation work, much of the department’s resources are also spent creating physical reconstructions of sculptural works from original fragments. This allows scholars to piece together works in stone that have survived only in fragments and view them in their overall original aesthetic context.
One of the most important restoration projects in recent decades was the successful reconstruction of a collection of sculptures dating from the early first millennium BCE, which were first exhibited in the Tell Halaf Museum in Berlin-Charlottenburg and which were destroyed during the Second World War. Within just nine years, from 2001 to 2010, the team of stone restorers, archaeologists, and mineralogists managed to reassemble the monumental artworks from more than 27,000 random fragments. The work often required them to fill in missing sections. The success of this endeavour has led to many international requests for details of the elaborate restoration methodology used, as well as for the team to share their experience with museums and institutions currently facing similar challenges.
The collection’s extensive ceramic holdings include glazed and unglazed pottery, some covered with engobe, as well as rare ceramic materials such as frit (blue frit) and objects made of glass, ivory, and bone. An ongoing department specialism is the conservation of the important collection of cuneiform tablets, many of which are composed of unfired clay or clay that was fired at very low temperatures. Such objects pose a great conservation challenge, both in terms of chemical degradation and climate control. As archaeological finds buried underground for millennia, they were all exposed to soluble salts. A further, ever expanding area of responsibility derives from previous unstable restoration treatments. In many cases, the removal of aged and thus no longer effective protective coats is not possible, because the substances have either become insoluble or cannot be extracted from the structure of the material. The expected standards for protective coats and their applications have risen, and so too has the depth of technical analysis and documentation that comes with any conservation or restoration treatment.
Archaeological bronzes are particularly vulnerable to complex corrosion processes that effect their state of preservation long after they are unearthed. The degree of deterioration depends on various factors, such as the specific nature of the electrochemical corrosion, the composition, depth, and humidity of the soil at the site, and the artefact’s fabrication technique. In the worst-case scenario, such factors can lead to the complete corrosion or mineralization of the object. In-depth knowledge of the chemical processes of corrosion is therefore an absolute prerequisite for treatments for the structural preservation of metalwork. What makes the Berlin collection unique is that many of the archaeological objects are still in the same state in which they were excavated. As a result, a particular specialism of the conservation studio is exposure, the removal of the soil environment and the products of corrosion to finally reveal the object’s original patina. Scientific analysis using x-radiography or computed tomography provides conclusive findings even in advance of any planned restoration treatment. Thanks to this technology, it was possible to detect a cuneiform inscription beneath the corrosion layer on a bronze cross from Assur before restoration even began, while hidden ridges on the inside of a small statuette shed light on the technique of hollow lost-wax casting in bronzes dating from the 3rd millennium BCE.