Human skin color neural, or viral causes. The incidence worldwide is less than 1%. Individuals affected by vitiligo sometimes suffer psychological discomfort because of their appearance. Increased melanin production, also known as hyperpigmentation, can be a few different phenomena: Aside from sun exposure and hormones, hyperpigmentation can be caused by skin damage, such as remnants of blemishes, wounds or rashes. This is especially true for those with darker skin tones. The most typical cause of darkened areas of skin, brown spots or areas of discoloration is unprotected sun exposure. Once incorrectly referred to as liver spots, these pigment problems are not connected with
Earth pigment the color can be deepened by heating (calcination) in a process known as "burning", although it does not involve oxidation but instead dehydration. Earth pigment Earth pigments are naturally occurring minerals containing metal oxides, principally iron oxides and manganese oxides, that have been used since prehistoric times as pigments. The primary types are ochre, sienna and umber. Earth pigments are known for their fast drying time in oil painting, relative inexpensiveness, and lightfastness. Cave paintings done in sienna still survive today. After mining, the mineral used for making a pigment is ground to a very fine powder (if not already