Reflectance transformation imaging for documenting changes through treatment of Joseon dynasty coins

Abstract We present reflectance transformation imaging (RTI) as a documentation tool for visualizing and recording the treatment of coins. RTI—a computational photograph technique that calculates light positions—allows interactive relighting vision. Virtual enhances surface details examining morphological difference. By applying Dome RTI method, stages conservation were recorded to enhance overall characteristic features relief upon coin surface, then detect identify weathered characters. Patina removal consolidation documented along with original state; significant difference in coin’s was observed using different filters viewer. Specular enhancement normal visualization results most effective detecting change morphology reflectivity. Microscopic applied visualized minimal changes characters between stages. Character “常” 1 showed cleaning dirt alumina powder. The character “元” 3, originally covered by thick patina, revealed clear strokes virtual through RTI. These images indicate is promising support manual and, furthermore, allow detection areas difficult visualize human eye.