What is a calotype? what happens in this process?

Cal·o·type
/ˈkaləˌtīp/

an early photographic process in which negatives were made using paper coated with silver iodide.

PROCESS ;

Calotype, also called talbotype, early photographic technique invented by William Henry Fox Talbot of Great Britain in the 1830s. In this technique, a sheet of paper coated with silver chloride was exposed to light in a camera obscura; those areas hit by light became dark in tone, yielding a negative image.