Avoiding the Blue and Black/White and Gold Argument: an Automated Colour Reference System Applied to Lithic Refit Processes

Since the first studies on lithic assemblage refitting, colour has been one of the main features considered by specialists looking for connections between artefacts. Colour has prevailed as a determinant element over other physical features such as roughness and grading, fractures or internal flaws and rock impurities. It appears logical to assume that two pieces of stone presenting identical or very similar colouring should have come from the same nodule or raw material block. However, despite the fact that the colour of an artefact is objective, its perception and determination depend on diverse subjective variables that make more arduous to measure and quantify it. Determining colour depends not only on the researcher’s personal evaluation but also on external factors such as the kinds of raw materials used, the degree of chromatic variability in the assemblage, and whether the analysis is performed in natural or artificial lighting conditions. In order to resolve these constraints, here we present the use of NODE+ ChromaPro in lithic refitting, which is a colour capture system that generates, based on colour models, such as RGB, CMYK, XYZ or Pantones, a colour code for each artefact. In this preliminary study, statistical analysis of the chromatic coding allows us to locate refitting lithic groups and raw material units in our sample from TD10.1 unit of Gran Dolina site (Sierra de Atapuerca, Spain). We go on to suggest that this automated process can be applied to search for lithic refits, where it should be implemented as a way to avoid subjective hurdles and how to obtain faster and more objective results.