MULTI/HYPERSPECTRAL AND SPECTRORADIOMETRIC ANALYSIS

During the 2025–26 fiscal year, the Pregraphity Research Group has been conducting digitization and multi- and hyperspectral analysis work for the Government of Cantabria and the Principality of Asturias. This work is part of a contract between the Leonardo Torres Quevedo Foundation at the University of Cantabria and the companies Jose Alcalá Ingenieros, S.L. (in Asturias), SCANNER PATRIMONIO E INDUSTRIA S.L., and Tecnitrop S.L. (Cantabria).

The study covered a total of 14 caves in Asturias and 30 caves in Cantabria between December 2025 and July 2026. All interventions were carried out under strict preventive conservation protocols, without directly affecting the rock surfaces or altering the environmental conditions of the caves, and were supervised at all times by a team designated by the regional governments.

The main purpose of the project was the spectral characterization of the decorated panels to optimize their visualization and chromatic classification. The specific objectives set forth in the technical specifications were:

• Pigment identification: Spectrally isolate pure pigments in each panel, as well as detect overlays, repainting, glazes, and possible pigments of modern origin.
• Radiometric calibration: Use spectroradiometric data to convert captured images into absolute reflectance values, enabling an analysis of class separability both within and across panels and between different cavities.

Priority has been given to the conservation of rock art over the volume of sampling, and data collection was not conducted in hard-to-reach areas that posed a risk. The results obtained represent a significant advance in the material characterization of Cantabrian Paleolithic rock art, providing a high-precision spectral database that ensures the traceability of the samples and enables future comparative studies. All technical documentation generated is included in the digital appendices of the final project report.

The caves where this work was carried out are as follows:

ASTURIAS