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The direct dyes are so called because they dye cotton without the aid of any mordanting process.

These three compounds are basic, and the first of them is no longer used as a direct dye because it is fugitive.

In dealing with the first of the above groups of dyes, the direct dyes, the colourist is somewhat at a loss to explain in what manner the combination with the cotton fibre is brought about.

Formerly the dyeing of these offered many difficulties before the application of the direct dyes was properly understood.

Referring first to the wool patterns and to the "direct dyes," we find that the only really fast colors are Prussian blue and Vat indigo blue.