Certain inks are specially formulated liquids used for writing, printing, or drawing. They can be made from various pigments or dyes mixed with a solvent, which helps the ink flow smoothly. Common types include ballpoint ink, gel ink, and watercolor ink, each serving different purposes and providing unique effects on paper. Some inks are designed to be permanent, while others are washable or erasable. For example, permanent ink is often used in markers and stamps, ensuring that the writing lasts over time. In contrast, washable ink is popular for children's art supplies, allowing for easy cleanup and removal from surfaces.