He was long thought to be from France and while he was in Japan he was even referred to as an "Englishman";[2] however, recent research has revealed that Rossier was Swiss, born on 16 July 1829 in Grandsivaz, a small village in the Canton of Fribourg.
At the age of sixteen he became a teacher at a school in a neighbouring village, but by 1855 he was issued a passport to visit France and England to work as a photographer.
[3] At some point after leaving Switzerland and arriving in England, Rossier was commissioned by the firm of Negretti and Zambra to travel to China to photograph the Second Opium War (1858–1860).
It may be that the firm considered Rossier's Swiss citizenship an asset for such a voyage, that his country's neutrality might help him find passage aboard either British or French ships.
[6] One of the photographs Rossier took during the summer of 1859, while in Nagasaki, was a portrait of Philipp Franz von Siebold's son Alexander and a group of samurai from the Nabeshima clan.
[7] At the end of June 1860, Rossier was in Shanghai, and it is likely that he visited the city in an attempt to gain permission to accompany the Anglo-French military expedition that had already arrived in northern China and thereby fulfill his commission to document the Second Opium War.
The British forces were accompanied by the photographers Felice Beato and John Papillon, and the French by Antoine Fauchery, Lieutenant-Colonel Du Pin, and possibly also by Louis Legrand.
[12] An 1861 edition of the Illustrated London News included several engravings under the collective title Domestic Life in China, the images having been taken from Rossier's stereographs.
[17] Nevertheless, in turn they taught wet-collodion process photography to Keisai Yoshio,[18] Furukawa Shumpei, Kawano Teizō, Maeda Genzō, Ueno Hikoma, and Horie Kuwajirō, among others.
[20] With Maeda and other students escorting him around the city, Rossier took photographs of priests, beggars, the audience of a sumo match, the foreign settlement, and the group portrait of Alexander von Siebold and samurai.
The encounter with Rossier seems to have convinced Ueno to pursue photography as a career, but he was so overwhelmed by the technology of the camera that he quickly dropped the notion of making one himself.
An 1871 advertisement in the French-language Fribourg newspaper La Liberté offered photographs by Rossier of religious paintings by the artist Melchior Paul von Deschwanden.
He complained at times of the adverse effects of the climate on his photographic chemicals and some of his negatives may have been damaged en route to London from Asia.