An ink blotter is a device which is designed to pick up extra ink on a handwritten document with the goal of preventing smears and bleeds. Ink blotters were ubiquitous through the middle of the 20th century, when people began using ballpoint pens, typewriters, and eventually personal computers to generate written material, rather than traditional quill pens. However, there are still some uses for ink blotters, and some art and stationery supply stores sell ink blotters for customers who use them.

Typically, an ink blotter is made from a curved block of metal, wood, bone, or plastic. The surface is designed to absorb ink directly, with the use of a material like felt, or with a piece of blotting paper, which can be attached to the ink blotter using special clips. The top of the ink blotter has a handle which can be grasped to manipulate it, and the blotter is often designed to fit into a case to keep a desk tidy and to prevent the ink blotter from rolling around when not in use.

To use an ink blotter, a writer would finish a document, pick up the ink blotter, and roll it gently across the surface of the document. The rolling motion would allow the ink blotter to pick up excess ink without causing the ink to smear during the blotting process, as long as the user lifted the ink blotter cleanly at the end of a roll. It might take several passes to cover the whole document, at which point it would usually be safe to touch without fear of smearing.

For writers, the ink blotter was an extremely useful development. Prior to the development of the blotter, absorbent materials like sand had to be scattered onto the paper, or loose sheets of blotting paper had to be carefully applied to finished documents. Using a whole sheet of blotting paper could create bleeding and smears, which would look unsightly, forcing the writer to start all over again. The ink blotter made the blotting process much more efficient.

People who work with traditional quill pens still use ink blotters for their original purpose. These utensils can also be useful for blotting ink drawings, watercolors, and other works of art with wet media, which is why many art supply stores carry them. Some people also collect vintage ink blotters, viewing them as interesting mementos of a bygone era.