Under the name of Kohol, an extremely fine powder, consisting of black sulphide of antimony, is used in Egypt by all classes for blackening the edges of the eyelids and the eyebrows.
A hair dye, much used in the Orient, is henna, the dried and pulverized leaves of Lawsonia inermis. By the women this powder is used for coloring the hair and nails red-brown. In the Turkish sweating baths the attendants scatter the henna upon the hair of the women and tie it upon the finger nails. The women then frequently remain for hours in the steam bath, whereby the powdered henna is converted into an extract-like mass which colors hair and nails red-brown. It is said that henna even colors the coal-black hair of the Arabs red-brown, which is considered beautiful. Before treating with henna, the hair must be freed from fat with soap or fuller's earth.
Hair dyed red with henna acquires a beautiful black color when subsequently treated with indigo, this mode of dyeing black being much in vogue in the Orient. The process is as follows: The hair, being freed from fat with soap, is divided into separate strands and anointed with quite a stiff paste prepared from pulverized henna and lukewarm water. The hair, after being smoothed, is allowed to remain for at least one hour in contact with the paste, and is then rinsed off with lukewarm water. Being slightly dried, it is then in the same manner anointed with a paste prepared from indigo and water, and allowed to remain in contact with it for one hour. The hairs which were colored orange-red by the henna, now have a greenish-black appearance, but by the oxidation of the indigo in a short time acquire an intensely blue-black color, which is extraordinarily durable, the hair only after several months requiring to be again dyed.
The freshly expressed juice and the fresh parenchyma of green walnut shells, or of unripe walnuts, gradually color light or gray hair dark to nut-brown. The coloring substance is not thoroughly known, but is very likely a phloroglucide; it is extracted by fats and alcohol, but, according to Paschkis, is no longer effective in such solution. This, however, is not correct in regard to the alcoholic extract, because the extract from ordinary walnut shells, prepared by mixing the expressed juice of green walnut shells with 10 parts of alcohol, allowing the mixture to stand for ten days, and then filtering, also colors brown.
Peroxide of hydrogen bleaches organic substances, dark or red hair being thereby changed to reddish-yellow or pale blonde. The coloration, or rather bleaching, does not appear at once, but is complete only after some time. The peroxide of hydrogen only exists in aqueous solution, which should be quite concentrated (15 to 20 per cent.). Owing to the mode of preparation, the solution always contains some nitric acid and readily decomposes, when exposed to light and air, whereby it becomes useless.
In the following, a number of formulæ for hair-dyes are given. According to their constitution, they may be divided into two groups, viz: A. Dyes which contain the coloring matter in a finished state; and, B. Dyes which are formed upon the hair by a chemical process. The dye should first be applied in a dilute state, and the application repeated in case the desired shade is not produced, since by the use of the dye in a concentrated form a shade not resembling any natural color might be obtained, hair which is to be colored black acquiring, for instance, a metallic blue-black lustre.
A. Single Hair Dyes. Teinture Orientale (Karsi).—Ambergris 2¾ drachms, gall-nuts 4 lbs., pulverized iron 1¾ ozs., pulverized copper 1 drachm, musk 1 drachm. Convert the gall-nuts to a fine powder, and roast the powder in an iron pan, stirring constantly until it is dark brown to blackish. Rub the powder together with the metallic powders, and the perfume substances and keep the mixture in a damp place. For use moisten some of the powder upon the hand and apply to the hair, rubbing it in vigorously. In a few days the hair acquires a deep black, quite natural color. In roasting, the tannin-substances contained in the gall-nuts are converted into gallic and pyrogallic acids, which yield with the metals combinations of a deep black color, and are even readily converted into black-brown bodies (humin bodies).
Teinture Chinoise (Kohol).—Gum-arabic 1 oz., Chinese ink 1¾ ozs., rose-water 1 quart. Reduce the gum-arabic and Chinese ink to fine powder, and triturate the powder in small quantities with rose water until a homogeneous black fluid free from grains is formed. Collect this fluid in a bottle and mix it with the remaining rose water. Kohol is only suitable for persons with black hair and is especially used for dyeing the eyebrows. The coloring matter of this preparation consisting only of carbon in a very finely divided state, it is perfectly harmless.