The Colour Shifting of Measuring Human Skin Colour Use Different Instruments

Abstract

Human skin colour information is important for the cosmetic industries and hospitals to develop a skin product and suggest an appropriate treatment. Human skin has multi-layered structures with non-flat surface and the colour of the human skin is unevenly distributed over the body. It is difficult to get skin colour information both exhaustively and precisely. Different ethnicities exhibit significantly different skin colour. To supply the data to the CIETC 1-92 Skin Colour Database and to achieve successful colour reproduction of skin colours on multimedia, two most widely used instruments, tele-spectroradiometers (TSRs) and spectrophotometers (SPs), were employed to collect large numbers of human skin colour, including 188 subjects from four ethnic groups (Oriental Caucasian, South Asian and African). Five or ten locations from each subject were measured. At each location, three repeated measurements performed by using both instruments and their mean values were used as the measurement results. The measurement results were reported using CIELAB colour system, in terms of lightness, chroma and hue. The colour distribution between different locations of different ethnic groups was studied by plotting the data points in a ^* b ^* and $L^{*} C_{ab}^{*}$ planes. Systematic trends were found between different ethnicities and instruments. The result shows a significant trend of the colour shifting between different ethnicities and instruments.