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 of the Ishihara colour perception test. The beginning of the book contains a quote from philosopher Alfred North Whitehead on the subject of colour: In a 2009 interview, the author mentioned two further books in the series. The titles "Painting by Numbers" and "The Gordini Protocols" have been suggested; however, neither is scheduled for publication as of June 2017. In a webchat, Fforde said a prequel to the series: "7 Things to Do Before You Die in Talgarth", may be published in 2019. Shades of Grey Shades of Grey: The Road to High Saffron (2012, simply titled Shades of Grey