The difference in people's complexions is due to the amount of melanin in the skin. The darker the complexion, the more melanin in the skin. Often, the different types of complexion are due to the difference in ethnic backgrounds. Complexions range from pale skin that burns easily and does not tan, or a complexion that is extremely tan and does not burn from the sun. Most people fall somewhere in between.
The type I kind of complexion is the most pale among all the skin tones. It is characterised by unusually fair skin, freckled and paperwhite skin. This pale skin always burns when exposed to the sun and rarely tans. Type 1 complexions are often found on natural redheads and some blue-eyed blonds. The type 1 complexion has the least amount of melanin of any complexion.
Type II and Type III complexions are light and usually pale. Type II complexion tends towards pale and often burns when exposed to the sun. It is possible to slightly tan with this complexion. Type III skin is light, but can also tend towards olive skin tones. It tans relatively easy, but can burn with too much sun exposure. People with this type of skin often have green or hazel eyes.
Two types of complexions found on those of Middle-Eastern and Mediterranean background are Type IV and Type V skin tones. Both are considered naturally tan, and tan easily in the sun. Type IV is brown skin and rarely,if ever, burns in the sun. Type V is dark brown and almost never burns.
Type VI is the complexion that contains the most melanin. It refers to black skin that does not ever burn with sun exposure. Type VI skin is often found among people of African descent. Although Type VI is already dark to black, it is possible to get even darker with sun exposure. Because of the high amount of melanin in the skin, it tans extraordinarily quickly.