What determines skin undertone?
Most of us know that melanin is the little pigment molecule that determines skin tone. This isn’t the whole story, though.
There are two main types of melanin called pheomelanin and eumelanin. Pheomelanin is a molecule that produces reddish/yellowish tints. This is also the same molecule that makes hair red. Eumelanin is slightly blackish-blue in appearance. Undertones do not change because they are based on the type of melanin that is predominant in your skin. However, skin damage and Father Time can change the outer layers sufficiently to make the undertones more apparent. Sunburns and rosacea, for example, may amplify pink undertones. You’ll always have the undertone you’re born with.
“Cool” undertones are from having more eumelanin than pheomelanin in the skin.
“Olive” undertones also have more eumelanin than pheomelanin in the skin, but there is just enough additional pheomelanin to give the skin a subtle green appearance.
“Neutral” undertones have a balance of nearly 50/50 eumelanin and pheomelanin.
“Warm” undertones are from having more pheomelanin than eumelanin in the skin.
FWIW: Heather is a neutral-cool with “light” skin. A good way to think about the light-to-dark ratio of your skin’s overall appearance as a reflection of the intensity of pigment molecules. It’s science, and it doesn’t assign a value based on these things. Also, remember that undertones are slightly different than your intensity levels. Light intensity tones can have olive undertones, and dark intensity tones can have cool undertones. We’re all unique. That makes finding your undertones kind of frustrating, but also interesting and very rewarding!