Antibacterial Seokganju Substitute Pigment Registered as Patent

Developed by the National Research Institute of Cultural Heritage Using Pyeongchang Red Shale
Antibacterial Properties More Than Three Times Higher Than Existing Pigments

The National Research Institute of Cultural Heritage announced on September 18 that it has registered a state-owned patent for a technology to manufacture a domestic pigment that not only replaces the traditional dancheong pigment seokganju but also possesses antibacterial properties. The official name is "Antibacterial Seokganju Substitute Pigment Containing Red Shale and Its Manufacturing Method."

Jongmyo Jeonjeon adorned with evening-colored dancheong / Cultural Heritage Administration.

Seokganju is a traditional pigment made from red soil or rock containing iron oxide. It is widely used for everything from priming wooden architectural structures to coloring decorative patterns. The institute has been conducting research to restore seokganju using the red clay (juto) from Hwangto Cave in Taeha-ri, Seo-myeon, Ulleung-gun, as documented in old literature. However, the designation of this area as a national geopark has created difficulty in sourcing the required raw materials.

In search of an alternative raw material, the institute identified red shale (a sedimentary rock formed from accumulated clay) found in Pyeongchang, Gangwon Province. After processing it in the traditional manner and comprehensively evaluating its physical properties, composition, and weather resistance, the researchers confirmed that both the color and performance were suitable as a substitute for the original seokganju. During this process, they also established process technologies, such as grinding, washing, and drying, to maintain consistent quality.

In tests that assessed the suppression of wood-decaying fungi, which damage wooden architectural heritage, the antibacterial property of the new pigment was found to be more than three times higher than that of the traditional juto pigment from Ulleungdo Hwangto Cave. It also fully met the quality standards of the traditional materials certification system announced by the Cultural Heritage Administration.

Red shale deposit area around Mitan-myeon, Pyeongchang-gun, Gangwon-do / GMA.

A representative from the institute said, "We plan to transfer this technology to private organizations to facilitate pigment production and practical use, and to apply it as a functional pigment at sites where national heritage is being restored."

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