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
Diarylide pigment with the same coupling partners. The molecular structures of these molecules is more conjugated than represented in the images shown below. The pigments' colors can range from yellow to green. One of the most common diarylide yellow pigments is Pigment Yellow 12. Its CAS number is . Other diarylide yellow pigments include ‘’’yellow 13’’’ , ‘’’yellow 17’’’ and ‘’’yellow 83’’’ . These pigments share the same backbone and vary in color depending on substitution of the benzene rings. Worldwide production of color organic pigments was estimated to be about 250,000 metric tons (t) in 2006, with about 25%, or 62,500