I. These colors being simply medium and light shades of violet, proceed
as for the latter color, selecting for heliotrope the bluish brands
of methyl violet, and for lilac the red touch mark. The dyebath is
acidified with a little tartaric acid, so as to give it a feeble
sourish taste and dyeing done at hand-heat until a level color is
obtained with very little solution of the dyestuff, and more of it
gradually added, while the temperature is raised to nearly boiling, as
required for the shade to be produced. Or,
II. Prepare the dyebath simply of cold water acidulated with a little
sulphuric acid, add a few drops of the filtered solution of methyl
violet (4 B. for heliotrope), and dye to shade without heating. In both
cases rinse after dyeing, pass through a bath of raw starch and dye as
usual.