The temple murals of Kerala, south India, are part of a remarkable artistic tradition dating from the 7th century CE to the present. These outdoor wall paintings, depicting Hindu themes, form a significant yet understudied heritage, offering insight into the religious, social and artistic practices in the region across centuries. Exposed to a tropical climate, they face environmental and anthropogenic threats to their material integrity, particularly from temple reconstruction. This study adopts a multidisciplinary approach to investigate the materials, condition and cultural value of these murals to guide conservation strategies.Five temple sites, representing both well-known and lesser-known temples, were studied: Eravimangalam Subramanyaswamy temple, Thrikodithanam Mahavishnu temple, Panayannarkavu Devi and Shiva temple, Pundareekapuram Vishnu temple and Annakara Annapoorneshwari temple. Documentation of the murals through digital photography was followed by non-invasive analysis such infrared (IR) imaging, hyperspectral imaging (HSI) and thermal imaging. More in-depth studies conducted at Thrikodithanam and Eravimangalam included fiber optics reflectance spectroscopy (FORS) for non-invasive characterization of painting materials. Furthermore, micro-sampling facilitated cross-sectional examination, elemental analysis using scanning-electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDS) and crystallographic analysis using X-Ray diffraction (XRD) crystallography.
Analysis revealed significant differences in green pigments between the two temples: copper trihydroxychlorides at Thrikodithanam and green earth at Eravimangalam. These findings carry important implications for both art history and conservation, challenging assumptions about continuity in the mural tradition. The results demonstrate that historical materials and techniques differ from contemporary practices regarding the use of indigo and gamboge for green while highlighting the need for site-specific conservation approaches, given the material variations in green pigments across temples.
Conservation concerns, such as flaking paint and plaster detachment, were more prominent in lesser-known temples. To enhance accessibility and awareness of these murals, high-resolution 3D models of the Thrikodithanam and Eravimangalam temple shrines were created, integrating scientific data from hyperspectral and thermal imaging. A dedicated website was developed to share these findings, promoting the preservation of Kerala’s mural heritage.
