Imaging and conservation strategies for archaeological iron objects

Iron objects are important in archaeological research due to properties such as their typology, manufacturing traces, and related organic remains. Due to the voluminous corrosion products and the decay of organic materials, the information contained in these objects is generally not accessible when they are left untreated. The decision is often made between either full treatment of all objects or no treatment at all. This research offers an alternative solution to the question of treatment versus no treatment. X-ray and μCT imaging techniques were applied to iron objects from the early Medieval cemetery of Lentseveld (in The Netherlands), and these methods were combined with selective, investigative, and full cleaning. These methods and techniques vary in their approaches and results, and combining them can be useful. The strategy depends on the needs of a particular project and specific research questions. Objects from such a context often have no metal left at all. After many centuries of post-depositional processes, they consist almost entirely of corrosion products. Of particular interest for this paper are the results that can be obtained using techniques such as μCT to see through corrosion and soil. The results include object outlines; internal structures and cross-sections; related objects; and associated materials. This research shows that applying and combining methods in a pragmatic manner has a clear advantage in terms of the achievable duration and obtainable information compared with the traditional strategy. It also suggests that μCT can contribute to both the conservation and interpretation of archaeological iron objects, especially larger object assemblages.