Throughout history, the artist has been a shaper of matter, whether the pigment of an image or the solid substance of sculpture. A Frontal Passage, like other works by Turrell, breaks from those ancient traditions in that it has no mass. Instead, Turrell shapes light.
An interest in a dematerialized art object appears in a range of work from the 1960s and 1970s—in Conceptual art, for example, which posits art more as language and idea than as visual form. But Turrell differs from the Conceptualists in the absorbing sensual power his work commands. He is closer to the Minimalist sculptor Dan Flavin, who also worked with light; but where Flavin would incorporate not only the light of fluorescent tubes but the tubes themselves into his art's appearance, the fluorescents in A Frontal Passage are obscured. The spec-tacle is light itself, given the illusion of palpable shape.
To view A Frontal Passage, the visitor passes through a darkened entryway into a chamber, also dark—but divided diagonally by a radiant yet crisply defined wall of red light. Instead of diffusing freely from one side of this wall to the other, the light ends abruptly in space, as if it had density. The power of the work lies in this paradox, in which nothingness gains physical presence.
from The Museum of Modern Art, MoMA Highlights, New York: The Museum of Modern Art, revised 2004, originally published 1999, p. 343