The study, published in Journal of Archaeological Science Reports and Journal of Cultural Heritage, also highlights that the analyses reveal a link between the composition of the red pigment — produced with binders such as milk, animal fat or resins — and the different stages of rock art in the Mediterranean arc.

Researchers Gianni Gallello and Mirco Ramacciotti, from the ArchaeChemis group (UV) and authors of both scientific papers, explain that the use of a low-cost tool makes it possible to identify differences between pictorial motifs comparable to those detected through portable X-ray analysis, albeit with lower resolution. The capacity to observe varying types of paint degradation suggests that the technique could be used as a screening and review method prior to undertaking other analytical procedures, and to support decision-making on the most appropriate subsequent analyses.

The significance of this methodology lies in its innovative non-invasive nature — as it does not alter the cave paintings — while simultaneously enabling the study of the alteration of the rock walls and the limitations of X-ray detection. “This technique opens new avenues for redefining the stylistic horizons of Mediterranean cave art”, concludes Gallello.

For the research, colourimetric data captured by the smartphone at the Levantine rock shelter were used. Taking into account the medium-to-large size of the images, their naturalistic style and precise anatomical proportions, the team identified design variations depending on the relative proportions between the torso and the legs and on the degree of muscular modelling represented. Three stylistic variants were identified at Cocó de la Gralla, confirmed through the analytical approach.

This study was carried out by researchers from ArchaeChemis and the French CNRS, together with researchers from the University of Valencia belonging to the Department of Prehistory, Archaeology and Ancient History, the Department of Analytical Chemistry and the Institute of Materials Science (ICMUV). The Centre for Rural Development–Museum of La Pauma of Mas de Barberans and the Geological Survey of Belgium also participated. The research was supported by the Archaeological and Palaeontological Heritage Service of the Department of Culture of the Government of Catalonia, within the framework of conservation activities and study of rock art in Catalonia.

Article references:

- Esther López-Montalvo, Gianni Gallello, Clodoaldo Roldán, Mirco Ramacciotti, Eric Goemaere, Angel Morales Rubio, Sonia Murcia-Mascaròs, Pepa Subirats. New insights into the Spanish Levantine rock art pigments combining pXRF and stylistic approach: The Coco de la Gralla site (Mas de Barberans, Tarragona, Spain) as a case study, Journal of Archaeological Science: Reports, Volume 66, 2025, 105273, ISSN 2352-409X, https://doi.org/10.1016/j.jasrep.2025.105273 

- Mirco Ramacciotti, Gianni Gallello, Esther López-Montalvo, Sonia Rubio-Barberá, Lidia Herreros Chavez, M. Luisa Cervera, Ángel Morales-Rubio, Sonia Murcia Mascarós, Clodoaldo Roldán-García. Developing a non-invasive approach for prehistoric rock art characterization based on smartphone imaging colorimetry and spectroscopy, Journal of Cultural Heritage, Volume 76, 2025, Pages 338-349, ISSN 1296-2074, https://doi.org/10.1016/j.culher.2025.10.019  

Captions in the annex:

1. Working group taking measurements with pXRF and smartphone.
2. Measurement with a smartphone.