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

Ties and bindings such as ropes, twines, cords, strings, and leather laces played a crucial role in Mesopotamian socioeconomic activities. However, due to the climatic conditions of the region, these perishable objects have survived only in exceptional circumstances, and 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, among others. 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 limitations, this study employs 3D digital modeling to generate non-invasive digital casts of negative impressions on four Ur III-period (ca. 2100–2000 b.c.e.) artifacts from the Ghent University Museum. This approach enables detailed analysis of features such as twist direction, cord diameter, and knot configuration, without compromising the integrity of the original artifacts. By integrating these digital reconstructions with archaeological and textual evidence, the study identifies the materials preserved as negative impressions on the clay as most likely derived from vegetable fibers, particularly rushes and grasses, and in at least one case leather, consistent with materials attested in cuneiform administrative texts, offering new insights into craft production and binding technologies in ancient Mesopotamia.