Excavations at Cardiff Castle were conducted in 2005-2006 in the footprint of the New Interpretation Centre. Cardiff Conservation Services, Cardiff University was contracted to conserve a selection of the materials recovered from the excavations. These materials consist of copper alloys, glass, iron, lead, semi-precious stone, shale, silver and wood. Conservation was conducted by Phil Parkes and Chris Wilkins in 2018-19.
A total of 890 small finds and context designations representing 2000+ individual objects were examined and/or treated between November (2018) and May (2019). Objects were categorised into five groups (A-E) rated by archaeological significance prior to entering the conservation laboratories. Groups A-C were determined to require some form of conservation treatment to clean, stabilize and reveal further information.
Intaglio with possible water horse carving. The upper left (a) micrograph is taken with reflective light coming from the left and right. The micrograph below that (b) is the intaglio taken with reflective and transmitted light. To the right are raking light micrographs of a SF414 mould with the light source on the right (c) or on the bottom (d) of the mould. The scales indicate 5 mm and are true for all four micrographs.
Examination, Documentation and Analysis
Before and after photographs were produced for all the conserved objects as part of the treatment documentation.The main examination and analysis methods are listed below.
Photography – Most objects were photographed with direct light. Coins were photographed with direct and raking light to highlight the surface details. Glass was photographed with direct light, transmitted light (i.e. light box beneath the object) and a combination of both. Transmitted light enables the observation of transparency of the glass. The intaglio was photographed using the same procedure as the glass with the addition of raking light to highlight the details of the carved surface.
Visual – The objects were examined in-hand and with optical stereo-microscopy.
X-Radiography – A Faxitron X-ray machine was operated at varying voltages and exposure times. The X-rays revealed details on structure, structural stability (e.g. cracks, fissures), decoration and a differentiation in material types (i.e. silver versus copper alloy coins). It also indicated whether additional cleaning was warranted.
Instrumental Analysis – Material types of some objects were identified using portable X-ray fluorescence (pXRF) qualitative analysis. A scanning electron microscopy (SEM) in conjunction with back scattered electron imagery (SEM-BSE) and energy dispersive X-ray analysis (SEM-EDX) was also used. BSE imagery provides a direct comparison of atomic mass with darker areas in the image representing lower atomic mass.
A small seletion of conserved finds that were discovered during the Cardiff Castle excavations