Size
Every year 250,000 tons of ink are used in the United Says. Since the 1994 Vegetable Ink Printing Act was passed by Congress, 22 percent of the ink used in the United States comes from soy oil. This law is an effort to reduce the use of toxic solvents in the manufacture of ink. It was passed to advance an environmental goal.
Types
Ink can be thought about in two categories: conventional ink for use in pens, for instance; and digital ink. Both types of ink begin with a base into which coloring agents, ingredients that control how it dries or how fast it flows, and other additives are blended. Both conventional and digital ink can be made with a water base. Both types can also be made using a solvent base. Finally, both types can be made using an ultra-violet cured base.
Features
Oil based inks are not used for digital printing, just for conventional use. The soy bean industry lobbied hard to get ink manufacturers to develop soy based recipes for ink. They have been so successful that soy ink now accounts for a fifth of the American ink market share. Petroleum oil based ink is also widely used in ink manufacturing. The whole printing industry actually grew up around 1460, after it was discovered that heated linseed oil made a stable base for ink. This is the oil that Gutenberg used to print his earliest Bibles.
Function
Ultra-violet cured bases for ink can be used in either conventional ink or digital ink. This kind of ink works the best on films or plastic surfaces. UV based inks don’t air dry like other inks. Instead, they produce a thick, flexible ink that, like plastic, stays where it is put. Water based ink cannot be used to print or write on film at all.
Expert Insight
Solvent based inks are the ideal to use if you’re printing on a non-absorbent surface like a white board. Wet-erase pens and dry-erase pens have solvent based ink. When their labels indicate that they conform to ASTM D-4236, they’re safe enough for children to use. If, however, the solvent base of the ink is highly toxic, the pen's label will contain a specific warning to that effect.