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Pen and ink
Pen and ink refers to a technique of drawing or writing, in which coloured (this includes black) ink is applied to paper using a pen or other stylus. It may be used as a medium for sketches, or for finished works of art. Pen and ink also lends itself to fine writing and calligraphy.
Different types of pens produce distinctive types of lines. Some, such as the crow-quill dip pen, produce slender and delicate lines. Other pens have a broader nib which can produce both thick and thin lines. Fountain pens and ballpoint pens are often regarded by many artists as being insensitive instruments or even not true "pen and ink" work, but are often useful for sketching in conditions in which a pot of ink would be a spill hazard.
Many technical artists prefer the Rapidograph series of technical pens, which produce lines of extremely regular width.
In art, pen and ink was originally used for quick sketches, often with a high degree of abstraction. George Romney produced a number of notable ink sketches of Emma Hamilton which are noted for the economy of his strokes, in which he produces instantly recognizable figures with a dozen lines. |
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Later artists developed the pen and ink drawing into a finished artform, and many interior illustrations in books and magazines are done in pen and ink because they do not require halftone screening, unlike continuous tone techniques such as ink wash or painting.
Pen and ink calligraphy was raised to a high level in Arabic, since Islam forbids the representation of living beings. In some forms of Arabic calligraphy, the letters were delicately formed to suggest an image related to the meaning of the phrase being written, without being an actual image of a living being. |
Ink
An ink is a liquid containing various pigments and/or dyes used for colouring a surface to render an image or text. Common perceptions consider ink for use in drawing or writing with a pen or brush. However, inks are used most extensively in printing.
Early varieties of ink include Indian ink, various natural dyes made from metals, the husk or outer covering of nuts or seeds, and sea creatures like the squid (known as sepia). India ink is black and originated in Asia. Walnut ink and iron-gall nut ink were made and used by many of the early masters to obtain the golden brown ink used for drawing.
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Pigmented inks contain other agents to ensure adhesion of the pigment to the surface and prevent its being removed by mechanical abrasion. These materials are typically referred to as resins (in solvent-based inks) or binding agents (in water-based inks).
Pigmented inks have the advantage when printing on paper that the pigment stays on the surface of the paper. This is desirable, because when more ink stays on the surface of the paper, less ink needs to be used to create the same intensity of colour.
Dyes, however, are generally much stronger and can produce more colour of a given density per unit of mass. However, because dyes are dissolved in the liquid phase, they have a tendency to soak into paper, thus making the ink less efficient and also potentially allowing for the ink to bleed at the edges, producing unsightly and poor-quality printing.
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To circumvent this problem, dye-based inks are made with solvents that dry rapidly or are used with quick-drying methods of printing, such as blowing hot air on the fresh print. Other methods to resolve this include harder paper sizing and more specialized paper coatings. The latter is particularly suited to inks that are used in non-industrial settings (and thus must conform to tighter toxicity and emission controls), such as ink jet printer inks, include coating the paper with a charged coating. If the dye has the opposite charge, then it is attracted to and retained by this coating, while the solvent soaks into the paper. Cellulose, the material that paper is made of, is also naturally charged, and so a compound that complexes with both the dye and the paper surface aids retention at the surface. Such a compound in common use i n ink-jet printing inks is polyvinyl pyrrolidone.
An additional advantage of dye-based ink systems is that the dye molecules interact chemically with other ink ingredients. This means that they can benefit more than pigmented ink from optical brighteners and colour-enhancing agents designed to increase the intensity and appearance of dyes. Because dyes get their colour from the interaction of electrons in their molecules, the way in which the electrons can move is determined by the charge and extent of electron delocalisation in the other ink ingredients. The colour emerges as a function of the light energy that falls on the dye. Thus, if an optical brightener or colour enhancer absorbs light energy and emits it through or with the dye, the appearance changes, as the spectrum of light re-emitted to the observer changes.
A disadvantage of dye-based inks is that they can be more susceptible to fading, especially when exposed to ultraviolet radiation as in sunlight.
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