Abstract: Objective To study the differences of melanin content and morphology in surface corneocytes between Black, White and Oriental skins. Methods Melanin content and distribution in surface corneocytes were measured by adhesive slide technique and Optomax V image analysis system in the exposed and unexposed skins from 10 Black Africans, 24 White Caucasians and 13 Orientals. Results There was significant difference of melanin levels in corneocytes among subjects with the three types of skin colour in both exposed areas (F=12.4,P<0.01)and unexposed areas (F=9.89, P<0.01),which correlated with the degree of melanin pigmentation of different race skins. It was also shown that melanin contents were higher in the exposed skin than those in unexposed skin in two racial groups (t=3.25, P<0.01), in Caucasians; t=3.31,P<0.01 in Orientals) except Blacks (t=1.22,P>0.05). It was observed that melanin granules were lighter in colour and smaller in size in corneocytes from Orientals than those from Blacks, but darker in colour and bigger in size than those from Whites.'Cap like structure' of melanin was seen in the cells from the pigmented skin. Conclusions The differences of melanin content and distribution in the corneocytes among Black, White and Oriental skins reflect different melanogenic capability to exposure of sunlight.

Key words: Racial stocks, Melanins, Keratinocytes, Image processing,computer assisted