IN HIS NEW National Gallery of Art retrospective, the late Dan Flavin (1933-96) paints the town red . . . and green, blue, yellow, pink, ultraviolet and four kinds of white.

Okay, not the whole town, or even most of the National Gallery's East Building, where it is nominally situated, but a substantial portion of it, at any rate. Sometimes it's just a corner of a room, sometimes an entire hallway. In one instance, Flavin's color spills out the window, distracting Pennsylvania Avenue drivers on the street below with its powerful otherworldly glow. That piece in particular, called "untitled (to you, Heiner, with admiration and affection)" is even said to be visible from passing airplanes.

His medium, you see, was not paint, but light. Fluorescent light, to be exact, in sculptural installations that, as a rule, make little attempt to hide the ugly, off-the-shelf hardware that makes their magic possible.

Make no mistake about it: It's magic, not decoration, that is taking place here.

Flavin's art isn't just pretty, but it is that -- and gets prettier as the chronological show progresses, especially the farther away one gets from his goofy, almost clownishly inept early attempts to incorporate light into his art. A roomful of pieces such as "icon VIII (to Blind Lemon Jefferson)," which features four blinking red incandescent bulbs in porcelain sockets affixed to a yellow Masonite box, is pretty hard to stomach, although it does lend credence to the notion that Flavin must have had a good sense of humor.

The problem with this first gallery is that the light-based works in it, dating from the very early 1960s, are still tethered to the picture plane, to canvases of a sort, as though Flavin hadn't yet figured out that the art gallery (or, in this case, the museum) itself was his canvas.

That came when the artist realized that a fluorescent tube alone, attached to a wall, as in "the diagonal of May 25, 1963 (to Constantin Brancusi)," was sufficient in itself to turn the wall on which it hung, as well as the room around it -- indeed, to turn the person standing in front of it -- into something other than what it was.

Certainly, one way in which this operates is the way paint does. Not artist's paint either, but humble house paint, which has been known to transform rooms, making them seem larger, or smaller, or more depressing, even to stimulate the appetite and the libido through the use of color. Yet color alone was not Flavin's sole tool. The element of light -- which burns, shimmers like a desert mirage and, in the shadows it casts and those it banishes, makes new the old -- invites us to see the world with new eyes.

Then again, there is the element of sculpture in Flavin's art, which treated the fluorescent tube, and its long metal box, not just as a necessary evil -- as a kind of unavoidable armature of sorts for the main act -- but as a virtue in and of itself. This is most apparent in Flavin's barrier pieces, such as "untitled (to Jan and Ron Greenberg)," and "untitled (in honor of Harold Joachim)," which both draw your attention toward and prevent physical access to the parts of the room they illuminate.

This frustration is part of what makes Flavin's art so interesting, and not just eye candy. Like moths to the flame (or, perhaps more appropriately, to the bug zapper), we are drawn to Flavin's art for its beauty and ethereality. But the closer we get to it, the more we see the deadly prosaicness of it.

Maybe this is what he was trying to get at by sticking light bulbs on boxes the way he did in those first, clumsy attempts. Maybe his point was not to make something look great, or more attractive, but just to make you look twice at it, or even away from it. Maybe by doing so, you'd come to realize that what he was really pointing at all along was somewhere else entirely.

DAN FLAVIN: A RETROSPECTIVE -- Through Jan. 9 at the National Gallery of Art, East Building, Fourth Street and Constitution Avenue NW (Metro: Archives/Navy Memorial). 202-737-4215 (TDD: 202-842-6176). Open Monday-Saturday 10 to 5; Sundays from 11 to 6. Free.

Public programs associated with the exhibition include:

Oct. 17, Nov. 21 and Dec. 5 from 1 to 3 -- Family workshop: "Color, Light, Space." Children ages 6 to 12 accompanied by an adult learn about Flavin's art and create their own glowing, Flavin-inspired works. Free. Preregistration is required. Call 202-789-3030.

Oct. 23-24 -- Jeffrey Weiss, curator and head of modern and contemporary art at the National Gallery, moderates a free symposium on minimal art and on Flavin's career. On Oct. 23 from 11 to 5, the program features slide lectures and a panel discussion; on Oct. 24 from 2 to 4, there will be a public interview with members of the art world who knew and worked with the artist. East Building large auditorium. Seating is first-come, first-served. Call 202-842-6826.

Nov. 3, 4, 17 and Dec. 12-15 at noon; Nov. 9 and 30 at 1 -- Gallery talks. Free.

Dan Flavin blends light, sculpture and color to create the two-sided, yellow and green "untitled (to Jan and Ron Greenberg)."