Daguerreotype

The daguerreotype is a type of photograph, developed by Louis Daguerre. 
 thumb | 205px| daguerreotype of Edgar Allen Poe
While the daguerreotype was not the first photographic process to be invented, earlier processes required hours for successful exposure, which made daguerreotype the first commercially viable photographic process and the first to permanently record and fix an image with exposure time compatible with portrait photography.