1. Context

Carbonless carbonless paper, launched in 1954, was one of the first applications of microencapsulation . The principle of this carbonless paper is based on the encapsulation of an oil containing a colorless ink, in gelatin capsules ranging from 1 to 10 μm in diameter. The reverse side of the paper sheets is covered with the microcapsules (several million capsules per cubic centimeter), while the front of subsequent sheets is coated with a chemical developer. Under mechanical pressure, such as that exerted by the tip of a pen, the shell of the capsules ruptures, releasing the ink which is colored by contact...