Electronic ink. Dr Joseph Jacobson holding micro- capsules from electronic ink on a spatula behind a magnifying glass. Paper coated in this ink can have text downloaded onto it electronically. The digital nature of the ink allows the text to be changed so a book can hold many titles. The ink consists of tiny transparent spheres containing microscopic white balls and a blue dye. When an electric current is applied, the balls, or microcapsules, rise up through the blue dye and become visible, or sink. By controlling where they rise and where they sink, a message can be formed. Jacobson, the ink's creator, works at MIT, USA. He co-founded the company E Ink to develop it.