Scientific American 42, 8.7.1848
For the Scientific American.
The famous purple of Tyre was said to be dyed from the blood of a shell fish found in the Mediterranean. If so, the art has long since been lost. A small insect named Kermes, supplied the place of the Tyrian purple until the discovery of America, which brought to light the cochineal insect, and a color is dyed by it far transcending all the ancient colors of oriental tale. From the great price of cochineal, however, it is a dear color at best to dye, hence many substances as substitutes for it have been tried, but none with so much success as the Lac- a half animal and half gum, very abundant in the East Indies and sold at a low price in comparison with cochineal. It is of a bluish color and sold in a powder at the Druggists for about 25 cents or less per pound. Four ounces will dye a red on a pound of woolen goods, as follows. The yarn or wool must be perfectly free from dirt and must be white. The lac in the proportion of two pounds to ten pounds of goods is steeped in weak mutiatic acid or the nitro muriate of tin for about 6 hours, when the lac will be found to be perfectly dissolved and of a red color. It is not possible to dissolve or melt it in water so as to make it give out or impart to the water its coloring matter without an acid. When the lac is thus dissolved, the dye kettle capable of holding the cloth or yarn should be boiling and the dissolved lac along with one pound four ounces of tartar put into it with nearly a pint of the nitro muriate of tin. After these have boiled for a few moments, the goods are loosely and carefully entered and boiled for one hour, when a fine red and as fast as cochineal, will have been imparted to the cloth. For coarse goods we recommend lac in preference to cochineal, but for fine goods and light shades, such as pinks, cochineal is the best.
By the above receipt any person may dye a lac red. It is easy dyed and quickly, far more so than by madder. Cochineal scarlet is dyed exactly like the lac red, only a little quercitron bark liquor is added to the dye boiler to produce scarlet. One ounce and a quarter of ground cochineal will dye a very deep red or scarlet. Two ounces of tartar are allowed for every ounce of cochineal - less will do, however. If no yellow is used in the dye kettle to make a scarlet color, the red after it is dyed may be made a deep crimson, by handling the goods in warm water and soda ley. - The lac red can even be blued, as it is technically termed, just by hot soda or pearlash liquor, to a deep and beautiful violet. The soda ley must not be too strong and the goods muct be handled for a long time, for a strong alkali not only injured the color but the fabric of the cloth, or fibre of woolen yarn. A beautiful pink can be dyed on cotton with cochineal, but as this color is known but to few and is not now in the field, we need not describe it at present. Lac is not used in the cotton or silk dyeing. Some use a small quantity of sumac in the lac dye kettle, they believing that it makes the color more permanent, but we do not approve of sumac in any manner being employed either for silk or wool.