Solvent ink is generally used to describe any type of ink that is not water-based. Solvent inks come in a wide variety from soft, mild, hard, true, strong, real, safe or green. To keep the ink in liquid form for jetting, the solvent is really just a carrier fluid and once the ink has been applied to the printed surface the solvent then evaporates. What solvent is used determines the drying time and type of application it is good for. The solvents vary widely from quick drying to slow drying. You will want to take into consideration what type of ink your printer is able to use, how fast you need the ink to dry, if your printer has a drying stage and what surface you will be printing on. Since some of the solvents can be toxic or harsh smelling you will need to ensure that you choose the right one for the ventilation in your printing area.