Computed Tomography, an aid to study techniques of artisanal processing of bronze ornamental elements dating back to the Iron Age

X-ray imaging constitutes a fundamental non-invasive approach for investigating the internal, otherwise inaccessible features of artworks and archaeological objects. Conventional radiography often provides sufficient information to identify material distributions, manufacturing techniques, and indicators of conservation state. While particularly effective for paintings and other planar artefacts, radiography may prove insufficient for complex objects or when image superposition hampers interpretation. In such cases, computed tomography is required to obtain a complete three-dimensional visualization of the artefact or archaeological find. This study is dedicated to the characterization of the craftsmanship of small bronze ornaments from northern Italy, with the aim of reinterpreting and modelling cultural interactions in Europe during the Early Iron Age. The project is based on the analysis of approximately 1200 copper-alloy adornments originating from six settlements associated with three interacting cultural areas: the Golasecca culture (north-eastern Piedmont), the Ligurian communities (southern Piedmont), and the indigenous groups of the western Po Valley. The excellent state of preservation of the artefacts, housed in three museums in France and Italy, together with the high quality of the archaeological documentation, enables an innovative and comprehensive investigation of northern Italian metallurgical practices. This study spans multiple scales, from the micro-scale analysis of surfaces and technical features to the macro-scale examination of workshop organization and interregional interactions, particularly with the Celtic world. By integrating archaeology, archaeometry, statistical analysis and data modelling, the project seeks to identify regional metallurgical traditions in north-western Italy and to address issues of techno-cultural transmission. Particular emphasis is placed on the role of artisans in shaping technological choices, social identities and the emergence of cultural groups during the Iron Age. Within this framework, reconstructing the chaîne opératoire represents a key challenge for understanding production strategies, technical variability, and the balance between innovation and tradition. This paper presents the X-ray imaging investigations conducted to date, with a specific focus on radiographic and tomographic analyses of a selection of fibulae from the settlements of San Polo and Villa del Foro. Although typologically comparable, these objects originate from different contexts. The study aims to identify the modelling and decorative techniques employed in their manufacture, thereby providing new insights into the production systems underlying these ornaments. Furthermore, the results contribute to assessing the existence of local metallurgical traditions and their possible transmission, adaptation, or transformation across cultural contexts.