La Chapelle, Disderi atelier. Albumen print, Getty Museum. Public domain photograph.

André-Adolphe-Eugène Disdéri (1819-1889) was a French photographer who pioneered the carte de visite, a small photographic print mounted on a card. He is credited with popularising this format, which became widespread in the mid-19th century and had a significant impact on portrait photography and mass communication. Disdéri's innovation made portrait photography more affordable and accessible to the general public, facilitating the exchange of portraits between friends, family and public figures. His work played a crucial role in the development of photography as both an art form and a means of social documentation.