Thomas Ruff's Portrait series, begun in the late 1980s, consists of an extended series of photographs taken of friends and colleagues at the Dsseldorf Academy, where Ruff studied. All are head-and-shoulder portraits, with subjects staring either directly into the camera or shot in profile. They face the camera without expression under flat fluorescent lighting, a format immediately reminiscent of passport photos, mug shots, or other institutional identification. The artist has often acknowledged the reference to identification photos in this work, and cites the increasing use of photographic modes of surveillance, especially Germany in the 1970s, as inspiration.

Ruff studied under Bernd and Hilla Becher and, like them, he consistently produces in serial form. Considered together, the ideological weight of the Portrait series represents Ruff's investigation into the nature and history of portrait photography.

Ruff has stated: "I don't think my portraits can present actual personalities. I'm not interested in making a copy of my own interpretation of a person. It's more my personal idea of photography that is accentuated in my portraits. I believe that photography can only reproduce the surface of things. The same applied to a portrait. I take photos of people the same way I would take photos of a plaster bust" (M. L. Syring and C. Vielhaber, "Thomas Ruff" in BiNationale, German Art of the Late 80's, Cologne, 1988, pp. 260-261).

Indeed, although they are personal acquaintances, Ruff's subjects are photographed with a profoundly cold and seemingly neutral eye. They are unidealized, unadorned, standardized portraits of apparent strangers. Ruff's camera scrutinizes in hyper-reality the frail imperfections of each face, and the viewer is left with a limited trove of details with which to assemble an imagined biography and psyche. They are precisely not the kind of photograph one would display at this size, especially when the subject is a stranger--and that, in some sense is the point.

Ruff refutes any subjective approach to photography and the conceit that images can provide insight into any a sense of interiority. In all of his works, he reduces the role of the camera to its most mechanical function: an instrument that visually records that which is in front of it. Individual images from the series may give us incidental insight into any one person's life, but taken as a whole the work resists the illusory "truths" of photography, insisting instead on the distinction between what we can know from such images and what we can only imagine.