From engineered standards to natural bone: re-constraining topographical scanning for heritage samples.

The microscopic topographical scanning of bone material is a common practice for multiple fields, such as archaeology, medicine, and criminology. However, assessments of whether the tools used to perform these scans are accurate on these objects have yet to be performed. In this work, the performance of the two most common scanning techniques used on bone items, focus variation and 3D confocal scanning, are preliminarily assessed, revealing previously unknown limitations with current measurement practice and technologies. Across a range of bone specimens, the same limitation appears, which does not occur on any of a subset of engineered materials tested. The types of features that bone-focused work would commonly asses, such as cutmarks, are revealed to be the most susceptible to distortion. 3D confocal is preliminarily determined as the more accurate technique to use on bone. The discrepancies discovered in this work begin to answer some of the unsolved repeatability problems noted during previous work on bone objects, and highlight how future equipment must be redesigned to accommodate this new style of emerging, critical, applications.