One of the basic limitations on visual perception is that it is impossible, in any given moment, to see the world sharply and full of colors beyond the central area of the visual field. A fundamental mystery of perception is the fact that people do not normally notice this basic limitation on what they can see in each glance. Indeed, many of the important differences between central vision in the fovea and more peripheral vision were not discovered until the 19th century and are still being investigated today. In order to truly capture the visual experience of an "impression" -- the vision of an instant -- an artistic work should contain only a single focus area in detail surrounded by peripheral areas of progressively greater blur. The work of the Italian sculptor Medardo Rosso (1858-1928) may be the first artistic representation of the difference between central and peripheral vision. Despite using the medium of sculpture, which is a three-dimensional representation, Rosso conceived of his work as two-dimensional because in a given moment it is possible to view a scene from only one viewpoint. One can estimate Rosso’s subjective impression of perception in a single moment by looking at his own photographs of the sculptures. In this talk, Rosso's photographs, which he used to recreate the visual effect that he wanted to represent, are used in several ways. First, an analysis of the areas of detail and relative blur allows a reconstruction of Rosso’s point de vue unique at which the artist wished the observer to stand when viewing that specific sculpture. Secondly, the photographs can be used to investigate Rosso's success as a phenomenologist of perception. The way in which the photographs become less detailed from the central focus toward the periphery can be quantified and compared to current models of perceptual acuity. The role of central and peripheral vision in subjective perception remains important to the work of many contemporary artists, yet Medardo Rosso’s monument d’un instant make him the first true "Impressionist".