From the Invisible to the Visible: 3D Digital Cast Creation and Analysis of Negative Impressions in Ur III Clay Objects

Fastening materials such as ropes, strings, and leather laces played a crucial role in Mesopotamian socio-economic activities. However, due to the climatic conditions of the region, these organic materials have not survived to the present day. Their presence is primarily attested through the negative impressions they left on various materials, most notably clay. Traditionally, such impressions have been studied using physical casting techniques involving plasticine, latex, or polymer clays. Although these methods can capture detailed surfaces, they are often invasive, time-consuming, and prone to residue deposition or inaccuracies due to shrinkage and distortion. To overcome these issues, this study employs three-dimensional digital modeling to produce non-invasive digital casts of negative impressions on four Ur III-period (ca. 2100-2000 BCE) artifacts from the Ghent University Museum. This approach enables the detailed analysis of features such as twist direction, cord diameter, and knot configuration, while fully preserving the integrity of the original artifacts. By integrating these digital reconstructions with archaeological and textual evidence, the study provides a new methodological framework for analyzing perishable materials in archaeology and deepens our understanding of ancient manufacturing techniques and cultural practices related to binding materials.