Martin–Schultz scale
The Martin–Schultz scale is a standard color scale commonly used in physical anthropology to establish more or less precisely the eye color of an individual; it was created by the anthropologists Rudolf Martin and Bruno K Schultz in the first half of the 20th century. The scale consists of 20 colors that correspond to the different eye colors observed in nature due to the amount of melanin in the iris :
- 1-2 : blue iris
- 3 : blue-gray iris
- 4 : gray iris
- 5 : blue-gray iris with yellow/brown spots
- 6 : gray-green iris with yellow/brown spots
- 7 : green iris
- 8 : green iris with yellow/brown spots
- 9-10-11 : light-brown and hazel iris
- 12-13 : medium brown iris
- 14-15-16 : dark-brown and black iris
