The Good, the Bad, and the Bumpy: Evaluating the Surface roughness Accuracy of Molding Compounds for Lithic Use-Wear Analysis.

The replication of microscopic surface features on stone tool edges using molds and casts is the only way to carry out use-wear analyses on certain lithic artifacts which cannot fit under a microscope or leave a museum. They are also very important for preserving wear stages in sequential experiments aiming to understand wear formation processes. However, the reliability of these methods for replicating micro-topographic features remains insufficiently explored. This study assesses the fidelity of three impression materials—Genie, President, and Affinis—on chert, dacite, obsidian, and quartzite tools, focusing on surface roughness replication for high-resolution analytical techniques such as confocal microscopy.Using Sensofar S-Neox microscopy, ceramic bead georeferencing, and Number of ISO 25178-based roughness parameters, we evaluated the precision and consistency of each material. Statistical analyses demonstrate that Genie replicated surface features with greater fidelity on dacite and obsidian, while President performed similarly on flint and quartzite. Among the evaluated parameters, Str (Texture aspect ratio), Smr1 (Peak material portion), and Sal (Autocorrelation length) varied the least and thus offered the highest replication quality.This research highlights the importance of selecting replication materials suited to the specific properties of the analyzed artifacts and the requirements of the applied analytical techniques. By providing a systematic framework for evaluating replication fidelity, this study contributes to improving methodological precision in use-wear studies and facilitates the application of advanced imaging technologies to archaeological research.