Terahertz Spectroscopic Analysis of the Vermilion Pigment in Free-Standing and Polyethylene-Mixed Forms.

Terahertz spectroscopy can be utilized as an effective nondestructive identification tool for the study of artist's pigments. Consequently, extensive measurements have been conducted on representative pigment species, and a few terahertz spectral databases have been constructed. However, the reported spectra were often acquired from pigment samples mixed with polyethylene at room temperature with low resolution, which often led to low-quality spectra with unresolved overlapping lines further broadened due to thermal effects.