Light skin of UVA can penetrate deeply into the dermis in persons with light skin pigmentation with little protective melanin pigment. The characteristic of fair skin, red hair, and freckling is associated with high amount of pheomelanin, little amounts of eumelanin. This phenotype is caused by a loss-of-function mutation in the melanocortin 1 receptor (MC1R) gene. However, variations in the MC1R gene sequence only have considerable influence on pigmentation in populations where red hair and extremely fair skin is prevalent. The gene variation’s primary effect is to promote eumelanin synthesis at the expense of pheomelanin synthesis, although this contributes to very little
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