Human skin color the liver. On lighter to medium skin tones, solar lentigenes emerge as small- to medium-sized brown patches of freckling that can grow and accumulate over time on areas of the body that receive the most unprotected sun exposure, such as the back of the hands, forearms, chest, and face. For those with darker skin colors, these discolorations can appear as patches or areas of ashen-gray skin. Melanin in the skin protects the body by absorbing solar radiation. In general, the more melanin there is in the skin the more solar radiation can be absorbed. Excessive solar radiation causes direct and
Chameleon heat more efficiently, then a lighter grey colour to reflect light during the heat of the day. It may show both colors at the same time, neatly separated left from right by the spine. For a long time it was thought that chameleons change colour by dispersion of pigment-containing organelles within their skin. However, research conducted in 2014 on panther chameleons has shown that pigment movement only represents part of the story. Chameleons have two superimposed layers within their skin that control their colour and thermoregulation. The top layer contains a lattice of guanine nanocrystals, and by exciting this lattice