Martin scale Martin scale The Martin scale is an older version of color scale commonly used in physical anthropology to establish more or less precisely the eye color of an individual; it was created by the anthropologist Martin in the first half of the 20th century. Later he improved this scale with cooperation of Dr. Schulz – the Martin-Schultz scale. The original Martin scale, summarized below, consists of 16 colors (from light blue to dark brown-black) that correspond to the different eye colors observed in nature due to the amount of melanin in the iris. The numbering is reversed in order to
Gardner color scale the liquid. This procedure isn't extremely accurate due to variations of observers, illumination and to some extent the standards themselves. Gardner Color can also be measured by a dual beam xenon flash spectrophotometer, for example the ColorQuest XT. Spectrophotometers measure the percent transmittance of the product and automatically calculate and provide the Gardner color number using illuminant C and 2º observer. Gardner color scale Gardner Color Scale is a one-dimensional scale to measure the shade of the color yellow. Colors of transparent liquids have been studied visually since the early 19th century. Changes in color can indicate contamination or impurities