The word INK has been variously defined by lexicographers, cyclophaedists and chemists, but the following terms may be taken as fully expressing the common qualities and essential specific characteristics of all substances included under the name.
INK is a colored liquid employed in making lines, characters or figures on surfaces capable of retaining the marks so made. The Encyclopedia Britannica, (vol. Xii. p. 382, 1856) gives the following definition: “INK – The term ink is usually restricted to the fluid employed in writing with a pen. Other kinds of ink are indicated by a second word, such as red ink, Indian ink, marking ink, sympathetic ink, printers’ ink, etc. Common ink is, however, sometimes distinguished as writing ink”.
As to COLOR – black is and has always been preferred in ordinary uses. For ornamental purposes and for occasionally useful distinctions, various other tints have been and are adopted – as blue, red, green, purple, violet, yellow – and so on, according to the fancy of the maker, or purchaser, or consumer.
The substance employed to receive and preserve the marks thus made is now almost universally paper. Parchment is still used in many legal documents and writings of form and ceremony. Cotton, linen and silk, when woven into fabrics for garments and like uses, are also subjected to marks of ink for the purpose of identifying property. So are wooden and leathern surfaces in similar conditions. It is also employed in writing on stone, in the quite modern art of lithography.
Though its great original and continual employment is in writing, it must be remembered that it is also largely used in the delineation of objects by artists. Ink and paint are mutually convertible to each others uses, but are yet so distinct in character and objects, that no one regards the words as synonymous, and no precise definition is needed to teach the distinction between them. As, for instance, in pen-and-ink drawings and sketches, the ink serves the purpose of paint so likewise in the letters on sign-boards & c. paint may be considered as a substitute for ink. The artist who traces his name on the canvas in a corner of his painting, employs paint in a similar manner. Printing-ink is used as black paint. In the best red inks, carmine (a paint in water-colors) is the essential ingredient. Indian ink is used here only as paint, - in China, as ink."