With his specialty, he built up an international career, often returning to schools, institutions and companies that he had worked with previously.

Based in Levallois-Perret near Paris, he worked throughout Europe, and beyond, for almost forty years, traveling as far as Norway, Russia, Greece and Brazil.

[2] On 8 October 1874 Jules David married Marie Cécile Mathilde Daman (1851-1929)[5] in Leuven, Belgium, where his wife was born.

This was not the case with Jules David who carefully prepared his travels and almost exclusively worked with clients who wanted more than a simple portrait.

As a rule, he would take a series of photographs of the building and its interior, he would then prepare a number of carefully composed group portraits of teachers and students, often complemented with 'action' photographs of students taking classes or involved in leisure activities.

[9] The finished product, often a luxury album bound in linen or red leather with imprints in gold, was sent free of charge to the head of the institution after which directors, teachers, students or employees would choose the images they wanted a copy of.

With his associate Edmond Vallois he ran a photo studio at the rue de Rennes[11] in Paris.

[12] Many of his negatives on glass were sold to the then flourishing picture postcard industry, which after his retirement remained an important source of income for his successor Vallois.

However, his reputation in France was not limited to 'school photography', as can be deducted from the prestigious commission to portray the French president Jules Grévy and his military staff in the garden of the Élysée Palace.

Théodore-Joseph Gravez, led in 1878 to the publication of the leather-bound album L'Episcopat Belge 1878, which included portraits of all Belgian bishops, their cathedrals and their episcopal palaces.

As in France and Belgium, his main clients were Catholic institutions, notably Jesuit and Ursuline boarding schools.

In Limerick, Ireland, he photographed the 9th Field Battery of the Royal Artillery in the courtyard of the Mulgrave Street barracks in 1898.

[15] In Norway the emphasis lay on school photography, although he also had firemen posing in front of his camera, as well as workers at an arms manufacturer (1890, 1892, 1893/94, 1895, 1898, 1899, 1903 and 1908).

[16] In Sweden his clients consisted of shipbuilders, a paper factory and a railway company, as well as schools and military institutions, including an equestrian portrait of Prince Carl, Duke of Västergötland (1892, 1894, 1900, 1901 and at least once between 1905 and 1910).

In Central and Eastern Europe he visited institutions and private enterprises in Poland, Moravia, Austria, Croatia, Hungary and Russia.

His furthest journey, as far as we know, took him to Brazil in 1906 where he spent several weeks taking photographs at the Colégio Militar in Rio de Janeiro, the Colégio Notre-Dame de Sion in Petrópolis, and the São Paulo Railway around São Paulo.