Solvent: This term is used to describe any ink that is not water-based. Piezo inkjet printers whose inks use petroleum or a petroleum by-product such as an acetone like carrier liquid. "Eco-Solvent" inks usually contain glycol esters or glycol ether esters and are slower drying. The resulting prints are waterproof. May be used to print directly on uncoated vinyl and other media as well as ridged substrates such as Painted/Coated Metal, Foam Board and PVC. The solvents soften the base material and allow the ink pigments to mechanically latch on to the chemically etched surface. Certain ink manufacturers have different bite based on what solvent carriers they use. Which is what makes solvent ink prints more durable than aqueous inks. However, solvent inks give off strong odor or fumes when drying, as the carrier fluid dissipates through applied heat from the printer's platen. There are various levels of solvent ink ranging from "True or Full Solvent" to "Medium/Mild Solvent" all the way down to "Eco-Solvent". The fume and odour levels decrease accordingly, so does the surface etch of the base material. Full to Medium/Mild Solvents require fume extraction to be considered safe in the working environment. Most Eco-Solvents can be used in an office environment with minimal or tolerable odor levels.