Chauvet Cave, France. Online resource, www.donsmaps.com, Public Domain.
Although in general we know that deep cave illumination had to have been done with fire, the details have been more assumed than scientifically verified – until now. A team of researchers led by Ma Angeles Medina-Alcaide from the University of Cantabria, Spain, and her colleagues have not only gone back to the archaeological data about light sources, they have conducted experiments to generate data about the effectiveness of the different options.
Archaeologists have found remaining traces of three different lighting systems in deep caves in Europe’s cave art regions. The first is open fire, the second is wood torches, and the third is represented by varieties of stone lamps burning animal fats. These artificial light sources allowed utilization of the dark zone deeper in the caves.
“Artificial lighting was a crucial physical resource for expanding complex social and economic behavior in Paleolithic groups. Furthermore, the control of fire allowed the development of the first symbolic behavior in deep caves, around 176 ky BP. These activities would increase during the Upper Paleolithic, when lighting residues proliferated at these sites.” (Medina-Alcaide et al. 2021)
“The luminous intensity, radius of action, type of radiation, and color temperature of the light determine the perception of the environment and the human use inside (such as the execution of art, funerary activities, and cave exploration). The light duration restricts the time spent inside the cave and defines whether the visit will be a long stay or a short exploration. Moreover, the optimal management of some of the produced gases (i.e., the smoke of lighting tools) is essential to carry out prolonged subterranean frequentation.” (Medina-Alcaide et al. 2021)
In other words, the factors that affect choice of light sources in the painted caves are; the intensity of the light desired, and the ease or difficulty of transporting material.
OPEN FIRE: An open fire would provide a great deal of light in such a dark cave, but to carry enough fuel to make it useful for any length of time would be a real challenge. Also, it would use up oxygen at a greater rate than a torch or a fat lamp. In Chauvet cave, “at least 10 fires were made by Paleolithic societies, using a total of 179 kg of fuel. The smoke dispersion would allow the fires to be replaced given the thermal stratification of the gases, and the hearths would be arranged in a tepee shape nearby but slightly away from the wall to accomplish this. These fires’ high radiation would be the main problem for human occupation when they were alight.” (Medina-Alcaide et al. 2021)
Although the remains of a number of fires have been found in deep caves this was not the most commonly used method of lighting.
Experimental torch illumination inside a cave. Photograph Mariángeles Medina- Alcaide et al., 2021.
TORCHES: In terms
of ease and convenience for the amount of light produced the torch would
probably have been the primary choice.
“Three peculiarities characterize the residues of torches: a) their dispersal location on the ground in caves, created by the intermittent fall of combustion residues (usually wood charcoals) along paths due to their use (such as the breadcrumbs in the story of Hansel and Gretel). b) Their location in the deep parts of the caves where the artificial lighting is indispensable. We can be sure that the fire resources were used for artificial lighting in these places without discarding other additional activities (such as space markers, refueling sites, or with more cultural or symbolic meaning ones). c) The confirmation of its location in primary position (discarding those combustion remains coming from other contexts outside of the cave). The residues of torches of Paleolithic age found in caves inner parts are usually limited to scattered charcoals above different surfaces, and black marks on the walls and ceilings.” (Medina-Alcaide et al. 2021) For any short duration purpose a torch would probably have been the optimum choice.
In construction, remains of torches were found to consist mostly of various pines and juniper. In addition, “Overall, green ivy and dry birch bark have been used to make the torches. These materials have not been identified at the moment in the examined contexts, perhaps due to preservation issues, but their availability has been characterized in other sites with Paleolithic chronology. In any case, they are useful materials for making torches, as evidenced by the remains found in favorable contexts for preservation but with more recent chronologies. Specifically, ivy has been used as a cord to unite the different elements that make up torches, and any other string-like element could replace this. Birch bark has been used to light fires due to its high flammability and rapid combustion.” (Medina-Alcaide et al. 2021)
Lighting experiment with an animal-fat-burning stone lamp. Photograph Mariángeles Medina-Alcaide et al., 2021.
FAT LAMPS: The optimum choice for long duration lighting would have been the fat lamp, although the amount of light provided would have been the least compared to the other available choices, and, in some contexts, transporting the lighted fat lamp could have been a real challenge.
“The animal fat lamps produced stable lighting for over an hour. Their luminous intensity was limited compared with torches and fireplaces, although for some functions (e.g., prolonged occupancy of the same place in a cave). Their radiation is not multidirectional. They emit a kind of semicircular halo; hence the light projected downwards is significantly less than that projected upwards and towards both sides. This is related to the small flame height relative to the lamp base’s size: the narrower the base and the higher the flame, the more light will be projected onto the floor. This lighting system does not produce smoke that could cloud and contaminate enclosed spaces. However, when pine resin was burning (and only when this fuel burned), the smoke added more pollution and blackening.” (Medina-Alcaide et al. 2021)
Studies of residues on actual stone lamps suggested that the fats were usually bovine or deer, often provided by lumps of bone marrow, and the wicks were often juniper, although examples of the use of porous bone wicks have been found. All in all the light of a stone lamp might be equated to a candle for each wick used in the lamp. For their scientific measurements and analysis I will refer readers to the paper listed below. There, you will find the team’s experimental results and data.
NOTE: Some images in this posting were retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them.
REFERENCE:
Ma Angeles Medina-Alcaide,
Diego Garate, Inaka Intxaurbe, Jose L. Sanchidrian, Olivia Rivero, Catherine
Ferrier, Ma Dolores Mesa, Jaime Perena, and Inaki Libano, 2021, The Conquest of the Dark
Spaces: An Experimental Approach to Lighting Systems in Paleolithic Caves,
16 June 2021, PLOS, https://doi.org/10.1371/journal.pone.0250497
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