Lamp for light: How temperature and humidity determine light management in Upper Paleolithic decorated cave environments

Analysis of lighting system management in Upper Paleolithic decorated caves is crucial to our understanding of the light sources used to create and observe depictions created deep in the interior halls. We developed a novel method for analyzing the environmental effects of the different light systems used in Upper Paleolithic caves. Our method uses a computer simulation to analyze the interplay between fire intensity, cave hall structure, and internal environmental conditions. We show that the potential for fire use in the deep interior halls is limited due to the dangerous conditions produced by the increase in environmental temperature combined with the cave's natural high humidity. To avoid serious heat-related illnesses such as heat stroke, careful management of the light system would be required. We identified cave opening height as the primary factor determining the safety parameters for human activity. We thus conclude that depictions located in deep, dark halls with a small entrance height must have been created using minimal artificial light.