Screen printing
inks can be used on a variety of subtracts.
Screen printing is an art medium that is accessible to anyone. Whether you are a novice crafter or a educated graphic designer, screen printing is an activity you can master with the right materials. Screen printing is very versatile; an image can be printed on almost anything using one of many types of screens or stencils. The one constant in the process is ink. There are various inks one can use when screen printing, and the need for one ink over another differs with each project.
Plastisol Ink
Plastisol ink is not water-soluble.
Plastisol is one of the most common inks used for screen printing on textiles. It is an easy ink to work with because it is sold in a ready-to-use state and can print on both light and dark fabrics. It is also popular because of its ease in curing/drying (via home oven or flash dryer) and its ability to be re-used. It is the ink of choice when printing on substrates such as T-shirts (both light and dark), sweatshirts, canvas and nylon. It is best on these materials because of its dense pigment and opaque nature. The ink does not penetrate into the fibers, but instead, after it has been cured, remains raised above the surface with a plastic shine. Plastisol is moderate- to high-priced when compared to its competitors, but its ability to be re-used may cancel out the price difference. Plastisol contains virtually no solvent. In order for an ink to dry, a solvent must be evaporated. Because plastisol has no solvent, it does not dry. This is an advantage when printing because the ink will not dry on the screen or mesh. This allows the printer to take breaks between projects or leave the inks exposed to the elements without having to worry about it drying up. Therefore, the ink left over from a project can be resealed in its original container and re-used in the future, thus saving money in the long run. Cleanup with plastisol inks is fairly easy. After the excess ink has been saved and resealed, the equipment, such as the screens and rollers, must be washed. Because plastisol has no solvent, a solvent must be used to rid the tools of the ink. The solvent and any contaminated ink pose environmental threats, so be sure to follow your state's hazardous waste procedures.
Water-based Ink
Water-based inks have a light hand: the ink is not raised above the fabric after curing.
Water-based inks are inks that use water as their main solvent. This type of ink is typically used for textile screen printing. It is popular for its smooth and easy printing, its low to moderate price and its soft, non-raised effect. Unlike plastisol, water-based inks penetrate the textile, and the cured ink does not sit above the fabric but instead becomes a part of it. There is no raised effect that can be felt by the hand. Because the ink penetrates the textile, water-based inks are not ideal for dark colored T-shirts and fabrics. Oftentimes, water-based inks are used for yardage projects or for fabrics such as kitchen towels and textile place mats. Water-based inks have water and co-solvents as their solvents. The solvents' ability to evaporate is cause for concern, as the ink can dry on the screens quickly and ruin an entire screen by clogging the mesh. Printers must pay close attention to how long a screen sits between projects. When curing a project, all the water must evaporate before the project is cured. This means longer and more difficult curing procedures than with plastisol. Likewise, water-based inks easily wear at the emulsion that creates a pattern on a screen. For this reason, screens have a shorter production life and extra costs are added to production for replacement screen or specific water-resistant emulsions.
UV Curable Inks
UV ink's popularity has exploded during screen printing in recent years because of its quick drying rate, lack of volatile organic compounds and sharp image. It is not popular or recommended for textile printing, but instead is popular for different substrates, such as plastic printing. UV ink is not as versatile as plastisol or water-based inks because the ink's opacity ranges from transparent to translucent, narrowing what it can be printed on. For instance, it cannot be used on dark substrates or on substrates that are exposed to outdoor extremes, such as sunlight. Curable inks, like plastisols, lack a solvent. This is, again, an advantage because the ink does not dry on the screen although, unlike plastisols, the curing process is extremely fast and easy. With the simple application of UV light, the ink dries in less than three seconds. The ink can be used on extremely fine mesh, which produces highly sought-after, crisp, clean lines. In order to make the most of the ink, shops would benefit by buying new screens in addition to having to buy UV curing sets and inks. The inks are worth the extra cost, though, because they do not evaporate, so very little ink needs to be used.
Other Choices
There are numerous other inks to choose from when screen printing, including discharge inks, expanding inks, suede inks, to name a few. Each ink serves a different purpose, requires a different curing process, has different costs and are effective on different substrates. Be sure to research each project in order to use the most appropriate ink and achieve the best results.
