Not all inks are alike. An ink is made from a pigment (colour) and a carrier, but that’s where the similarities end! There are three different types of inks, based on how the inks dry: evaporation, thermosetting, and UV (ultraviolet light) exposure.
Inks that dry by evaporation, can be water or solvent based. Solvent based inks dry very quickly but come with some environmental concerns about volatile organic compounds in the atmosphere. Water based inks dry more slowly, but don’t contribute any pollution to the environment. Many printing places use evaporation inks exclusively — but that doesn’t mean they only have one type of ink. Some inks are multipurpose; others are used only on specific substrates (printing surfaces).
Thermosetting inks are not often seen in sign printing, but are widely used in t-shirt and textile printing. These inks cure, rather than dry, and are liquid until exposed to heat. Epoxy inks are often heat-cured, too, and are used on glass, metal, ceramics, and some plastics.
Inks that are cured by ultraviolet light are growing more popular, but require a big investment on the part of the printer. UV inks are often found in high-volume printing operations, and do not contain the volatile organic compounds found in solvent-based inks. That means they’re free of environmentally harmful emissions. Hopefully, the price of UV drying equipment will go down and consumers will see UV inks from more printers.
Most printers use some type of evaporation inks in creating your custom printing projects. Choosing a particular ink, has an impact on many different factors — not just drying. An ink determines what type of mesh you use in screen printing and what kind of stencil should be used.
If you’ll be printing on an unusual substrate, your printer may need to use a different type of ink! Even different types of plastic use different types of ink for screen printing. The same goes for different types of metal or even different coatings on paper. Your printing professional will be able to choose the right ink for your printing project. If you’re especially nervous about your ink and materials, you can ask about the possibility of test prints. Your printer can print some samples and let them dry; after twenty four hours, it’s time to put the printed material under every stress you can think of Scratch the ink with your fingernails, rub at it with a cloth, stick tape onto the ink and try to peel the ink off.
A test print may add a little extra time to your project, but it can be worth it if you want to print on something really unusual. It’s better to take the time and get it right, rather than rush through and watch your ink peel or flake off your promo items.