In its most simple form, an ink is composed of pigment and solvent. The pigment gives the ink its hue, while the solvent is the vehicle that carries the colour.
Pigment comes from a variety of sources with nitrogen-containing compounds, commonly known as dyes. Solvent is derived from soybean oil, linseed oil or a heavy petroleum distillate.
Inks run the gamut from pen to printer, and different types of ink have very different applications.
These types of ink are made with a water base, and are therefore very cost-effective. They are used, for example, in fountain pens. They deliver rich, bright colours which don’t smudge easily. The small molecular structure of the dyes used allows for immediate absorption while reflecting and scattering very little light, contributing to their vibrancy.
The water base allows the ink to be soaked into the paper or surface being inked. As the ink is absorbed into the surface, it stains it. One disadvantage of water-based ink is that it has a tendency to bleed. Because dye-based inks are water soluble, they’re quick to run or smear upon contact with water or humidity – regardless of how long it’s had to dry beforehand.
This characteristic can be used in an artistic way to create a water-colour effect: lightly spray porous paper with water before applying the ink and watch it feather on the page.
Dye-based inks dry quickly and are most often used for card making and scrapbooking.
Many dye-based inks are acid free, but colours will fade over time. The small molecular makeup of the dye means that water-based inks are highly susceptible to oxidation and fading, and the colours they produce usually don’t last very long. Excessive exposure to sunlight or UV rays will accelerate fading.
Another drawback of dye-based inks is unintended overlapping of separate colours, due to the fast-absorbing nature of the ink.
Pigment-based inks are made from pigments suspended in a glycerine or resin base. They are generally more expensive than water-based ink and are used, for example, in gel pens.
Unlike dye-based inks, pigment-based inks do not stain the paper or surface – they sit on top of it instead. This means that less pigment-based ink than dye-based ink will be used similar colour intensity. Pigment-based inks can be more vibrant than their dye-based counterparts, and work very well on matte paper or embossed paper.
However, these inks will not dry on glossy paper.
Pigment-based inks a favourite with crafters and scrap-bookers because they do not fade that much over time. In fact, they can retain much of their original vibrancy for a century, as long as the correct type of paper is used. This is because each colour is made up of a neutral base and tiny coloured particles. These particles aren’t organic and don’t break down to mix with the liquid – and therefore don’t break down in sunlight either.
This mixture of a neutral base and pigmented colour produces a slightly diluted pattern, so the printed result is often less vibrant than would be the initial dye-based version.
Pigment-based inks are also great for embossing. They take longer to dry than water-based inks, ensuring enough time to work with the embossing powders.
Because pigment-based inks can’t be absorbed by traditional paper, pigment ink is more susceptible to smudging if it isn’t allowed to thoroughly dry before handling.
Solid inks are a relatively new addition to the world of print. Solid inks are vegetable oil-based, wax-like blocks that are melted and applied to paper. Similar to pigment-based inks, solid inks remain on the surface of paper instead of being absorbed by it. This means they are durable and won’t fade much over time.
The results of solid ink printing are often more vivid than those of pigment-based inks, because the printed colours aren’t broken up by a neutral base.
This type of ink offers an environmental advantage as they are not housed in plastic cartridges that require disposal.
A big downside to solid inks is their lack of availability and their relatively high price point.
Other types of ink
There are a number of different types of ink that occur in the world of print, but they are often used for very specific industries.
Solvent inks contain colour pigments and organic chemical compounds that become waterproof after being treated with heaters. They are used in the production of decals, banners, billboards and artwork on plastic goods.
UV-curable inks become colour-rich polymers when their acrylic molecules are saturated with direct UV rays. They are used to print on stainless steel, glass, wood, ceramic and other materials.
Dye-sublimation inks contain a type of dye that transfers to fabric when heated. This type of ink is used to manufacture T-shirts, caps, flags and other cloth materials.