Early globalized industrial chain revealed by residual submicron pigment particles in Chinese imperial blue-and-white porcelains

Significance Our knowledge of the pigment provenance of blue-and-white porcelain is based primarily on the Fe/Mn criteria, which contradicts the archaeological concept (including typological evidence like blue hue, bleeding effect, iron spots) and historical records. Here we propose a reliable method for tracing cobalt sources through the microstructural analysis of submicron residual pigment particles to avoid influence from elemental fractionation. An application of the method to the Xuande imperial productions demonstrates that an intentional approach of mixing imported and domestic cobalt ores was adopted, which could rationalize all of the apparent contradictions between compositional data and conventional authentication. Our findings further suggest that the overseas pigments continued to play an irreplaceable role from 15th century onward as the globalized trading network began to break free of regional political affairs.