Chromogenic mechanisms of overglaze red pigment produced in the Jingdezhen kiln during the Ming dynasty

Chromogenic mechanisms of overglaze red pigment produced in the Jingdezhen kiln during the Ming dynasty

To elucidate the compositions and chromogenic mechanisms of overglaze red pigment produced in the Jingdezhen kiln duringthe Ming dynasty, we employed energy-dispersive X-ray fluorescence spectrometry, Raman microspectroscopy, scanningelectron microscopy, and single-factor simulations to analyse 16 specimens of overglaze pigment porcelain fired in theJingdezhen kiln during the Ming dynasty. Results indicated that α-Fe2O3 crystals are the chromogenic agent in overglaze redpigments. However, the composition and crystallinity of the α-Fe2O3 crystals varied among specimens. Overglaze red pigmentproduced before the Chenghua era had a low Fe2O3 content and mostly exhibited a bright red hue, whereas those producedfrom the Chenghua era onwards had more diverse compositions and appeared bright red or dark red. The overglaze redpigment produced during the Jiajing era had high Fe2O3 and PbO content and were generally found to have a deep red hue. Simulation experiments indicated that increasing the calcination temperature of FeSO4·7H2O results in greater disruptionof the long-range order of α-Fe2O3 crystals, thereby producing deeper hues of red. The results of the study will be of greatsignificance for the conservation and identification of overglaze red pigment porcelain in the Jingdezhen kiln.

To elucidate the compositions and chromogenic mechanisms of overglaze red pigment produced in the Jingdezhen kiln duringthe Ming dynasty, we employed energy-dispersive X-ray fluorescence spectrometry, Raman microspectroscopy, scanningelectron microscopy, and single-factor simulations to analyse 16 specimens of overglaze pigment porcelain fired in theJingdezhen kiln during the Ming dynasty. Results indicated that α-Fe2O3 crystals are the chromogenic agent in overglaze redpigments. However, the composition and crystallinity of the α-Fe2O3 crystals varied among specimens. Overglaze red pigmentproduced before the Chenghua era had a low Fe2O3 content and mostly exhibited a bright red hue, whereas those producedfrom the Chenghua era onwards had more diverse compositions and appeared bright red or dark red. The overglaze redpigment produced during the Jiajing era had high Fe2O3 and PbO content and were generally found to have a deep red hue. Simulation experiments indicated that increasing the calcination temperature of FeSO4·7H2O results in greater disruptionof the long-range order of α-Fe2O3 crystals, thereby producing deeper hues of red. The results of the study will be of greatsignificance for the conservation and identification of overglaze red pigment porcelain in the Jingdezhen kiln.