Nadar sought to create psychological impressions of his subjects. This is one aspect in which the idea of "progress" shaped his portrait style. Nadar was influenced by the idea that what was on the surface is merely a prelude to what existed underneath it Photography was his forum in illuminating this condition of being. This is where the late 19th Century idea of progress could be seen in Nadar's work. Nadar sought to reveal the "psychological profile" of his subject, reflective of the progressive notion that photography does not necessarily have to capture what is. It can encapsulate what can or should be. At the same time, the technical style of Nadar's photography was influenced by progress. Varying styles in lighting and background usage as well as experimentation with negative development techniques are all areas in which progress impacted the technical approach that Nadar appropriated in his work. The idea of "progress" helped to shape the portrait style and approach that Nadar took towards his work.