Oil-based inks are printing inks made primarily from pigments suspended in oil, typically derived from plants or petroleum. These inks are known for their rich colors and durability, making them suitable for various printing methods, including offset printing and letterpress. They dry through a process of oxidation, which can take longer than other types of inks. One of the main advantages of oil-based inks is their resistance to fading and water, ensuring that printed materials maintain their quality over time. However, they can be more challenging to clean up compared to water-based inks, requiring solvents for removal.