Rhatany.
Rhatany root furnishes a reddish-brown coloring matter which is soluble in alcohol and is extracted with it from the comminuted root, especially for tooth tinctures and mouth washes. For the same purpose use may also be made of red santal wood and Pernambuco wood which likewise yield to alcohol, besides astringents, beautiful colors which are very suitable for such preparations.
Green Colors.
Chlorophyll.
The green coloring matter of leaves is easily extracted from them, when bruised, with alcohol, and is left behind after the evaporation of the solvent. Some powders which are to have a green color are mixed directly with dried and finely divided bright green leaves such as spinach, celery, parsley leaves, etc.
For soap it is customary to use a mixture of yellow and blue which together produce a green color. Take a yellow soap, melt it, and add to it the finest powder of smalt or ultramarine until the desired tint is obtained. Indigo-carmine cannot be used, as it would impart a blue color to the skin.
Blue Colors.
For many preparations smalt or ultramarine is employed, but these colors are insoluble. The only soluble blue colors are aniline blue and indigo-carmine; the latter has a beautiful and intense color, but is suitable only for pomades and not for soaps because, as stated above, it would stain the skin.
Violet
is produced by a mixture of red and blue in due proportions.