Human hair color used in physical anthropology and medicine to determine the shades of hair color. The scale uses the following designations: A (very light blond), B to E (light blond), F to L (blond), M to O (dark blond), P to T (light brown to brown), U to Y (dark brown/black) and Roman numerals I to IV (red) and V to VI (red blond). Brown hair is characterized by higher levels of eumelanin and lower levels of pheomelanin. Of the two types of eumelanin (black and brown), brown-haired people have brown eumelanin; they also usually have medium-thick strands of hair. Brown-haired girls
Shades of Grey the town close to the lower of a series of five dams suggests it is Rhayader, at the foot of the Elan Valley. Nearby Rusty Hill was once Builth Wells. The town of Vermillion used to be Hereford. The town of High Saffron is on the coast beyond the dams, which suggests Aberystwyth. The colour values as described in the book supposedly come from the Munsell color system as described by Albert Henry Munsell, but are derived from the HSV color model. The "Ishihara", a test used to determine one's colour vision, is a reference to Shinobu Ishihara, the inventor