Scientific American 10, 2.9.1868
A beautiful green color, devoid of poisonous properties, economical, and useful for confectioners, can be obtained as follows: 5 grs. of saffron are shaken up with ¼ oz. of distilled water, and the mixture allowed to stand 24 hours; at the same time, 4 grs. of indigo carmine are shaken up with ½ oz. of distilled water, and the mixture also allowed to stand for 24 hours. At the end of this time the two solutions are mixed together, which produce a very fine green solution, capable of coloring no less than 5 lbs. of sugar.