Roopak Goswami
Guwahati, Nov 17: In a major boost for India’s traditional pottery sector, researchers at the National Institute of Technology (NIT) Rourkela have patented a sustainable, fast and pollution-free method for producing black terracotta – a craft traditionally dependent on long firing cycles, specialised clay and smoke-intensive processes.
The new technique reduces the firing time from nearly two days to under seven hours, offering artisans an eco-friendly alternative that preserves the signature shine and deep black finish of heritage pottery.
The innovation is the result of years of research by a team led by Professor Swadesh Kumar Pratihar, Department of Ceramic Engineering, along with Shiv Kumar Verma, Senior Technical Assistant, and Rupesh Mandal, research graduate. Their patented process (Patent No. 572754, Application No. 202531008090) blends centuries-old knowledge with modern ceramic science.
Terracotta (literally ‘baked earth’ in Italian) is one of India’s oldest craft traditions. While red terracotta is widely produced using common clay fired in air, black terracotta demands intricate techniques. From the famed Nizamabad black pottery of Uttar Pradesh, which relies on a kabiz glaze and mustard oil polishing, to the smoke-based blackening in Nixi village of Tibet, the craft typically involves long firing cycles, skilled hands and heavy use of organic fuels like cow dung, straw and wood chips.
But these traditional methods come with high costs: toxic emissions, heavy smoke and health risks such as respiratory problems for artisans.
The NIT Rourkela breakthrough changes that.
Explaining the science behind the method, Pratihar said, “The sustainable process merges traditional artisan knowledge with modern technology. The key is indirect heating in an air-depleted chamber. Pyrolysis of carbonaceous oil generates carbon monoxide and soot, creating the reducing atmosphere needed to produce black wares – without open fires or pollution.”
The method ensures a uniform black finish, requires no specialised clay or expert-level skill and eliminates the environmental footprint associated with burning organic material. Crucially, it allows black terracotta to be produced anywhere, potentially reviving the craft in regions where traditional resources are scarce. Experts say the patented technology not only supports India’s commitment to sustainable craft production but also opens new possibilities for artisans, entrepreneurs and designers looking to scale black pottery for modern markets.
