Evaluating the suitability of lithic illustrations in morphometric analyses

Illustrations of lithic artefacts are an abundant source of morphological and technological information for those interested in our human past, trusted as faithful reproductions of the selected artefacts in question. Despite the considerable epistemic work which lithic illustrations (and illustrators) are expected to do, usually little information is available regarding the illustrator’s technical skill; thus it remains unknown whether drawings produced by illustrators of differing technical skill are comparable, or produce images of equal analytical potential to other conventional forms of media including photographs. The issue of illustration faithfulness is brought to the fore by the recent emergence of geometric morphometric (GMM) approaches as innovative and powerful ways of describing and analysing complex shapes – and lithic illustrations provide one of the key sources for such analyses. Motivated by these issues, we present an experiment investigating the degree of error observed in illustrations (illustration-object accuracy) of differing technical illustrative skill. Initial analyses suggest that lithic illustrations, produced by individuals with a variety of experience in drawing lithics, create, in the majority of instances, faithful representations (in outline shape) of chipped stone artefacts when compared to other conventional methods. Despite this, error was observed in a small number of instances, and archaeologists are still urged to be critical of an illustration’s source prior to data analysis. Overall, archaeologists can be fairly confident in the exactitude of lithic illustrations produced following the creation of standardised illustrative conventions, and their suitability as a readily available legacy resource for morphometric analyses.