I love stories about colours and their origins, but this one on Paris Green is especially good: This Trendy But Toxic Shade of Green Left Thousands Dead in the Victorian Era.
Turns out 19th century patrons loved this tint that was produced using…arsenic. You can imagine how this turns out, but save your imagination and read the story.
Image and story from Town and Country, of all things. Not sure how I came across it, but I am glad I did.