Turkey blue

Silk is dyed blue with indigo alone, without any proportion of woad... with ſix pounds of bran, and about twelve ounces of madder... half a pound of madder for each pound of potaſh, renders the vat greener, and produces a more fixed colour in the ſilk... it is wrung out, and expoſed to the air, that the green colour may change to a blue... Some addition is required to be made to the indigo, to give ſilk a deep blue... For the Turkey blue, which is the deepeſt, a ſtrong bath of archil is firſt prepared. Conchineal is alſo ſometimes uſed, inftead of archil, for the ground, to render the colour more permanent.