Human hair color account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person's genotype for a multifactorial trait can interact with the environment to produce varying phenotypes (see quantitative trait locus). Natural hair color can be brown, blond, black, red, or white; all natural hair colors including grey, white and lightest blond, are shades of brown. The Fischer–Saller scale, named after Eugen Fischer and , is
Buff (colour) with a black top" in order to indicate their ownership. There is some uncertainty among experts, however, as to the exact shade of what is now called "White Star buff". There is no surviving paint or formula, and although there are many painted postcards and at least seven colour photographs of White Star liners, the shades of the funnels in these varies due to many factors including the conditions under which they were originally made and the ageing of the pigments in which they were printed. Speaking mostly to scale modellers, the Titanic Research and Modeling Association currently recommend a