Uncovering The Formula For a Mysterious, Medieval Blue Ink

For thousands and thousands of years a purple-blue ink known as folium was used to color all kinds of books, cheese rinds and more, but its formula was lost until a team of researchers recently deciphered the recipe through three ancient texts. It’s long been confirmed that the dye comes from the fruit of chrozophora tinctoria, but this isn’t a complete assessment. By poring over the …