The sources which make it possible to restore the first systemic excavations of Roman archaeological sites from the late-republican and imperial period in Algeria are particularly rare for this region of North Africa. Along with the Edmond Duthoit archives, those of Albert Ballu are among the first identified corpora that demonstrate a more or less continuous record of the exploration of the Timgad site. The Architecture and Heritage Media Library (MAP) retains all of the photographic coverage produced during the thirty years that Ballu’s work will last. By relying on a statistical and sequential analysis methodology and a rigorous descriptive system, it will be a question of studying the survey protocol adopted between 1892 and 1927, while questioning the material use of photography for the practice of photography. excavation in Roman archeology, between the end of the 19th century and the beginning of the 20th century.