Hayes, John L. (John Lord), 1812-1887 · Boston : Press of John Wilson and Son · leaf 24
NOTES UPON INDIGO. … The leaves which surround the stem are collected in May or June of the second year, when they begin to turn yellow. The wasted and dried leaves are sometimes used directly for dyeing, but more generally the leaves, after being cut and dried, are carried to a mill, and then ground to a paste, after…
Indigo · Dyes and dyeing
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
