Medium brown skin:
Medium brown skin is common in many subtropical and tropical regions of the world. It roughly corresponds to a Luschan scale of 18-23. Depending on the region, it may show an olive, yellowish, or copperish tone. Apart from Europe, it is frequent in certain populations of all continents. In Africa, many groups of the Sahara as well as Khoisans and a few forest populations show medium brown skin. It is widespread in South and South-East Asians, and many Native Americans who live in tropical or subtropical climate. The tropical Mongoloid groups have a thicker stratum corneum, which gives a yellowish tint. It protects better against solar radiation, thus the selective pressure to develop dark skin is reduced. In addition, these groups migrated relatively late to their current habitat. Medium brown skin shows a good protection against solar radiation. It can burn in untanned skin. Many early human groups probably possessed this skin tone.