Two new shows by leading New York art photographers Robert Mapplethorpe and Joel-Peter Witkin inevitably invite comparison.

For classical, pristine images of beautiful bodies and flowers, and luscious textures, see Mapplethorpe at Middendorf.

For surreal, theatrical tableaux constructed from deformed bodies and severed limbs, all redolent of the dark, dank demimonde, see Witkin at Tartt. But see him on an empty stomach.

They could not be more unlike: Mapplethorpe celebrates things as they are, including love and lust, while Witkin's fictions wallow in darkness, disease and death. But there have been excesses in the work of both of these artists, and what unites them -- apart from their great current success -- is that both first attracted attention with shocking images, often featuring boots, whips and chains, confrontational sex and homosexuality.

Witkin's current show finds him roughly where he was two years ago at Tartt, still arranging ever denser (and somewhat tiresome) dramas at the same old meat market. Mapplethorpe, however, has reached a new pinnacle in a series of very large, unique black-and-white photographs (on the main floor at Middendorf) that have all the power and presence of paintings -- a challenge rarely won.

They underscore how traditional Mapplethorpe really is, not only in his subject matter, but in his concern with classical composition. "The Chest," for example, a commanding image of muscular crossed arms framing a muscular chest (a frame within a frame, given the wide black frame around it) -- it's a rectilinear composition, yet so full of curves that the figure somehow begins to be read as a dark cavernous landscape. Every pore is visible, even a small scar on the hand -- all observed with an intensity the artist transmits to the viewer.

There is a still life of a radiant orchid that seems to levitate over a vase, and another of a marble urn with fruit and drapery that echoes baroque painting, yet somehow skews scale to suggest a size and monumentality that this small urn cannot possibly have.

The show is centered by a haunting image of roses, bunched as if hung on a door to signify death -- a notion reinforced by a thick horizontal black stripe across the center. The roses have almost anthropomorphic overtones, as we sense a bit of wilt in the leaves -- not dead but dying. The walls of the gallery have been painted gray, amplifying a sense of mourning, as well as an awareness of the broad range of grays in these images. Of the eight photographs in this new suite of work, three are masterpieces.

Upstairs, among smaller and generally less impressive works, are male and female nudes observed from odd angles and in torque that Edward Weston would have loved -- especially the man who appears to be imitating a green pepper.

Mapplethorpe's show continues at Middendorf, 2009 Columbia Rd. NW, through Feb. 27. Witkin's show closes the same day at Tartt, 2017 Q St. NW.

The Blount Collection If forming an art collection -- private or corporate -- has ever crossed your mind, see "American Masterpieces From Blount Inc." at the Federal Reserve.

Then be sure the same thing doesn't happen to you.

A classic lesson in how not to collect, this group of 30 paintings (selected from 100 in the Blount corporate collection) is a perfect illustration of how buying "names" rather than quality can doom a collection to mediocrity -- to wit, examples by such famous artists as John Singleton Copley, Frederick Church, William Merritt Chase and Georgia O'Keeffe. There are worse examples here, notably a painting by Walt Kuhn, which has to be one of his worst.

There are, to be sure, a few strong examples on view, notably an 1882 still life with lobster by trompe l'oeil master William Harnett, and watercolors by Winslow Homer, Maurice Prendergast and Charles Burchfield, who makes an especially strong showing. There is a curious but stiff painting of Grand Central Station by John Sloan, and a first-rate, hard-edged semiabstract "Third Avenue El" by Ralston Crawford. The collection's signature work, Edward Hopper's "New York Office" -- a characteristic study in urban isolation -- is somehow equaled if not bettered by Guy Pene du Bois' image of a couple dining in a restaurant.

As is usually the case in collections of this sort, some of the more memorable works are by artists who are lesser known (and their best works thus more easily acquired). Among the highlights: an energetic New York harbor scene with tugs by Jonas Lie (1880-1940), a smoky Pittsburgh view titled "Mill on the River" by Aaron Harry Gorson (l869-1944) and a Gauguin-inspired "House on the Hill" by Anne Goldthwaite (1869-1944), whose own "Mill on the River" was included in the famous Armory Show.

N.C. Wyeth's "The Steelworker," a heroic, muscular image celebrating the American worker, proves yet again his superiority over his son Andrew, the only living artist in this unadventurous show. Andrew Wyeth is represented here by a large watercolor titled "Outward Bound" -- a nonsensical seascape with a beached cannon pointlessly poised to blow a sailboat out of the water.

The collection -- formed over the past 15 years by former postmaster general Winton M. Blount, now chairman of the Alabama construction and engineering firm that bears his name -- will eventually go to a museum in Montgomery, Ala.

What the museum will get -- in addition to a handful of fine pictures -- is a time capsule showing what was acquired by a late 20th-century American collector who -- apparently lacking either the time or the expertise required to discern quality himself -- left choices to others, in this case a dealer who seems to have done little to elevate his client's taste.

But can the dealer be blamed? In a market with growing numbers of moneyed collectors and dwindling numbers of first-rate works of art, the best examples inevitably go to museums or to collectors who demand quality and know the difference. It's not so much a question of who's to blame as it is a problem of the underlying goal -- putting together a comprehensive history of American art at this late date -- being wrongheaded and therefore doomed to failure.

The exhibition can be seen through March 18 at the old Federal Reserve Board Building, C Street between 20th and 21st streets NW. Hours are 11:30 a.m. to 2 p.m. Tuesdays through Fridays, or by appointment (452-3686).