▁effects . ▁ ▁The ▁actual ▁skin ▁color ▁of ▁different ▁humans ▁is ▁affected ▁by ▁many ▁subst ances , ▁although ▁the ▁single ▁most ▁important ▁subst ance ▁determ ining ▁human ▁skin ▁color ▁is ▁the ▁p ig ment ▁mel an in . ▁Mel an in ▁is ▁produced ▁within ▁the ▁skin ▁in ▁cells ▁called ▁mel an ocy tes ▁and ▁it ▁is ▁the ▁main ▁determin ant ▁of ▁the ▁skin ▁color ▁of ▁dark er - sk inned ▁humans . ▁The ▁skin ▁color ▁of ▁people ▁with ▁light ▁skin ▁is ▁determined ▁mainly ▁by ▁the ▁bl u ish - white ▁connect ive ▁t issue ▁under ▁the ▁der mis ▁and ▁by ▁the ▁hem og lo bin ▁circul ating ▁in ▁the ▁ve ins ▁of ▁the ▁der mis . ▁The ▁red ▁color ▁underlying ▁the ▁skin ▁becomes ▁more ▁visible , ▁especially ▁in ▁the ▁face , ▁when , ▁as ▁consequence ▁of ▁physical ▁exercise ▁or ▁the ▁stim ulation ▁of ▁the ▁nerv ous ▁system ▁( anger , ▁fear ), ▁ar ter i oles ▁dil ate . ▁ ▁There ▁are ▁at ▁least ▁five ▁different ▁p ig ments ▁that ▁determine ▁the ▁color ▁of ▁the ▁skin . ▁These ▁p ig ments ▁are ▁present ▁at ▁different ▁levels ▁and ▁places . ▁Mel an in : ▁It ▁is ▁brown ▁in ▁color ▁and ▁present ▁in ▁the ▁bas al ▁layer ▁of ▁the ▁e pid erm is . ▁Mel ano id : ▁It ▁res emb les ▁mel an in ▁but ▁is ▁present ▁diffus ely ▁throughout ▁the ▁e pid erm is . ▁Car ot ene : ▁This ▁p ig ment ▁is ▁yellow ▁to ▁orange ▁in ▁color . ▁It ▁is ▁present