Scientific American 21, 22.11.1862
The basis of indelible ink is nitrate of silver. Such ink is chiefly used for marking linen for the purpose of withstanding the bleaching action of washing and exposure to the sun. Jules Guiller's indelible ink is made of nitrate of silver by weight, 5 parts, distilled water 12, powdered gum arabic 5, carbonate of soda 7, ammonia 10. These ingredients are mixed together and heated in a flask until the mixture acquires a dark tint. This ink may be thickened with sufficient gum mucilage to print indelible marks with type.
Redwood's indelible ink is prepared as follows: - Dissolve one ounce of nitrate of silver and one and a half of crystallized carbonate of soda in separate portions of distilled water, then mix them together when they will form a precipitate; this is collected in a filter and washed with distilled water. It is now placed in a porcelain mortar and 8 scruples of tartaric acid added and the whole triturated until effervescence ceases. Next add a quantity of ammonia to dissolve the tartrate of silver and mix with it 4 fluid drachms of archil, 4 of white sugar and 12 of powdered gum arabic; then pour in as much distilled water as will make 6 ounces of the mixture. This indelible ink differs from the common kind in the substitution of the tartrate for the nitrate of silver.
Another more simple indelible ink is made as follows: - Take 6 drachms of nitrate of silver and dissolve in 3 ounces of distilled water and as much ammonia is added as will liquify a precipitate of the silver, which occurs at first. A little neutralized sulphate of indigo is now added and 4 drachms of gum arabic mucilage, when it is ready. These inks should be kept in red glass bottles, or where they will be excluded from the action of light. The cloth after being marked with such ink should be exposed to light, and also slight heat before the fire, or the heat of a flat-iron. If cloth is first prepared with a solution of the chloride of tin, then washed and dried, and afterward written upon with a solution of terchloride of gold, ad indelible black is also formed.
An ammonical solution of a salt of gold, mixed with a portion of the indelible ink made with the tartrate of silver, produces a superior indelible ink, but it is too expensive for common use.
A purple red indelible ink is made with a solution of 1 drachm of bichloride of platinum in 2 ounces of distilled water. The linen must be prepared to receive it by first being moistened on the part to be marked with a solution of 3 drachms of carbonate of soda and 3 drachms of gum arabic in an ounce and a half of water, and then dried.
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