Often times skin tone and undertone are used interchangeably. When using skin tone it typically refers to whether someone is light, fair, medium, or dark. Undertone on the other hand, usually mean being cool or warm.
Cool undertones are usually revealed in fair skinned people, those who appear more pink than peachy, dark brown skins with red tones, skin that looks bronze or brown when tanned. While warm undertones are reflected in people who can easily Tan themselves, who appears more peachy and with visible yellow tones.
Our skin comes in various colors and these colors are called as skin tone. The skin color is due to the presence of melanin in the skin. Lighter skin tone has lesser melanin while darker skin tone has more melanin. Melanin is formed by skin cells called melanocytes. It provides a defense to our body against the harmful ultraviolet rays (UV rays). If the skin is not protected from the harmful rays of the sun, it can result in a severe skin condition or even skin cancer. So how does melanin work? When the UV rays start reaching your skin, the melanocytes works and functions to produce melanin, in effect the skin changes color. The longer you expose your skin to the UV rays, the darker your skin tone. However, people with fair skin can be hardly tanned because their skin has fewer melanocytes hence produces lesser melanin.
Some people have naturally dark skin tone even without exposing to the UV rays. This is explained by researchers as part of the evolution. Studies show that people who have darker skin tone have ancestors who once lived in tropical regions where the harsh UV rays reached their skin.
It is important to know what your skin tone is in order to protect it from the damaging effects. Those who have fairer skin are at a greater risk of skin cancer because they have lesser melanin in their skin compare to people who have darker skin tone. If you are aware that you have darker skin tone, then you may not need to put on higher SPF sunscreen. Treatment for skin conditions also varies from the type of skin tone you have because of the presence of melanin. Melanins react when the skin is irritated, especially with medications.
A Harvard dermatologist, Thomas B. Fitzpatrick, proposed 6 skin types that are listed according to their lightness. According to the skin tone chart there are 6 types of skin tone.
Type I : White (very fair)
They are characterized by pale white skin and usually have freckles.
Type II: Fair or light-skinned European
They have white skin with light or dark hair color.
Type III: Medium, dark-skinned European
White to light brown skin color with brown hair color.
Type IV: Dark Intermediate, Mediterranean or Olive
Moderate brown skin color with black to dark brown hair
Type V: Dark Brown
Naturally dark brown skin color with black hair.
Type VI: Black
Very dark brown to black skin tone with black hair.