"a colour almost like the backing of mirrors"
Woman looking in mirror, crayon drawing, 1918
According to answers.com
, "Silver was the most popular mirror backing one hundred years ago. . . . More recently, before 1940, mirror manufacturers used mercury because it spread evenly over the surface of the glass and did not tarnish. This practice . . . posed the problem of sealing in the toxic liquid. Today, aluminum is the most commonly used metallic coating for mirrors."