Swell Paper

A special paper coated with heat-sensitive microcapsules that swell when exposed to heat, creating raised tactile surfaces from printed black areas. When passed through a heating device (such as a PIAF — Pictures In A Flash — machine), dark-printed lines and shapes become raised bumps that can be felt by touch. Swell paper is widely used to create tactile graphics, maps, charts, and diagrams for blind and visually impaired users, offering a low-cost alternative to braille embossers and 3D printing for producing tactile educational materials.