Objective:Using the data from normal tongue and lip colors of normal people which were collected by the visible reflection spectrum, we analyzed the colorimetric parameters of tongue and lip colors.

Methods:In this study, 516 healthy students aging from 19 to 26 from the colleges and universities of Guangdong Province of China were taken as research subjects. After collecting the data of tongue and lip colors of the 516 subjects using visible reflectance spectroscopy, CIE XYZ tristimulus values as defined by the International Commission on Illumination in 1964 were calculated, and the colorimetric parameters of the normal tongue and lip colors were obtained, such as the CIE 1964 chromaticity coordinate, brightness, dominant wavelength and excitation purity.

Results:The results of CIE 1964 chromaticity diagram calculated on the visible reflection spectrum showed that the normal tongue color chromaticity coordinate x10 was 0.3413±0.0085 and y10 was 0.3326±0.0051, and the normal lip color chromaticity coordinate x10 was 0.3577±0.0092 and y10 was 0.338 3±0.005 7; the brightness Y values of the normal tongue color and lip colors were 17.96±3.78 and 19.78±3.72, the dominant wavelength values of the normal tongue color and lip color were (626.3±51.6) nm and (600.4±18.2) nm, and the excitation purity values of the normal tongue color and lip color were 0.083±0.031 and 0.144±0.036, respectively.

Conclusion:Application of the visible reflection spectrum is a standard way to collect colorimetric data for inspection of the complexion. The investigation of chromaticity coordinates, brightness, dominant wavelength and excitation purity of the normal tongue and lip colors may offer the basic reference for diagnosing morbid complexion on the tongue and lip colors in traditional Chinese medicine.

Key words: inspection, tongue inspection, objectifying tongue inspection, lip, light, XYZ tristimulus values, brightness, dominant wavelength, chromaticity coordinates, excitation purity