Emoji skin tone modifiers are based on which dermatology scale?

Emoji skin tone modifiers are based on the Fitzpatrick scale.

Unicode’s emoji modifiers draw on the Fitzpatrick scale, a dermatological classification system for human skin response to ultraviolet exposure. The scale has six traditional skin types, numbered I through VI, ranging from very light to very dark responses.

Unicode added five emoji modifier characters in Version 8.0, released in 2015. One modifier represents Fitzpatrick types I–II together, while the other four correspond broadly to types III, IV, V, and VI. These modifiers are encoded from U+1F3FB through U+1F3FF and can follow compatible people, hand, or body-part emoji.

The emoji shades are not medical measurements and are not exact color replicas of the dermatological categories. Platforms choose their own artwork, so the visible colors can differ between Apple, Google, Microsoft, and other systems. The Beaufort scale measures wind force, while Likert and Glasgow scales serve unrelated survey and clinical purposes.