There is something at once disconcerting and exhilarating about the sheer nuttiness involved in the making of Ellen Gallagher’s work. Labor intensity of sisyphian proportions underwrite her endeavors, which often entail mind numbing detail or fractional variations over a repeated series. This is nowhere more true than in her ongoing, monumental sequence of murals – begun in 2001 with “Falls and Flips”

and continuing at a pace of one mammoth panel a year – composed of manipulated advertisements from vintage African-American publications. Her current exhibition at Gagosian unites the earlier panels with two new ones from 2004, “Afrylic” and “eXelento.”

The projected series is to include eight panels, all structured similarly as grids of 396 ads arranged in canvases of 8-by-11 feet. The ads promote such wares as skin lighteners, hair straighteners, wigs, and other products that are less overtly (though in the artist’s mind still significantly) inflected by racial prejudice: Corns, bunions, or asthma, for instance, are conditions to which impoverished manual workers and their families are prone.

The artist “whites out” such features as lips, hair, or wigs with yellow plasticine. These then stand out from the surface as a kind of sculptural relief, lovingly formed elements that read as voluptuous ornamentation. They accentuate precisely the racial attributes the products were intended to diminish. The malleable putty is striated and carved in ways that recall African tribal art, although that’s not the exclusive cultural reference.

The five panels form the centerpiece of an impressive, demanding exhibition in which several bodies of work, diverse in medium and mood, share common themes of negritude and mutation. Several manipulated movies, witty and poignant, play simultaneously in a darkened room: they draw on vintage jungle pictures. Big, minimal-seeming works on paper belie their purist first impression by showing, close-up, an imagery that evokes skeletal and scale-like organisms from the ocean bed or prehistory, built through precionist perforations of the page. Into the mix, an incongruous discovery upon close examination, are “primitive” minute African heads. “Watery Ecstatic,” (2003), for instance, has them pop up on a serpentine form that recalls the Book of Kells in its serene complexity.

The most compelling room, however, remains the chapel-like, wraparound installation of panels, with their grim newsprint source materials and contrastively jolly plasticine addenda. Almost an altarpiece to ambiguity, this deeply strange work is at once serial and surreal, combining sharp sociopolitical critique and soft-focus personal poetic invention.

Ms. Gallagher’s knowing fusion of fine craft and strident agenda will inevitably draw comparisons with Kara Walker, whose scintillatingly perverse silhouettes of riotous antebellum “blaxploitation” belong to the same subgenre. But Ms. Gallagher’s work is less over-the-top, less in-your-face than Ms. Walker’s. There is a subtler divorce between craft involvement in the generation of images and what the facture might mean for them. The clean, machine cut vinyl Ms. Walker works in betrays an alienation of expressive means and ends (which can be interpreted as intentional). Ms. Gallagher does something more diffuse, and harder to define: She creates a primordial vocabulary of shapes by correcting the weirdness and wrongness of attitudes afflicting a particular community in a given historical moment. She manipulates the manipulated.

Actually the artist Ms. Gallagher seems most closely to resemble, thanks to the odd mix of the menacing and the oceanic in her invented morphology, is the recently rediscovered Lee Bontecou.

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Alex Katz is one of those artists, like de Kooning and Picasso, whose greatness can be measured in the number of imitators and acolytes they can count. It is quantity, not quality, that matters – otherwise all three would be in trouble.

In Mr. Katz’s case, his imagery has been more influential than his technique, which is far harder to emulate. Two painters up in Chelsea right now seem to be in awe of his ability to convey distinct mood while withholding overt expression, either facial or painterly. James Rielly, showing at Galeria Ramis Barquet, and Brian Calvin, at Anton Kern, are not to be dismissed as camp followers, however; both are serious and substantial painters for those willing to look, with sympathy, past the “ditsyness” of their faux naive genre.

Mr. Calvin shares with Elizabeth Peyton a twin allegiance to Mr. Katz and David Hockney, though Ms. Peyton’s mood is much more finely wrought and edgy. A typical Calvin has dopey-looking youths in suburban interiors: Mr. Katz provides the attitude and openness of form, Mr. Hockney the awkwardness and the Californian potted plants. They can lay equal claim – should they covet the honor – to the cartoonish conveyance of such optical details as light shining on glass.

Many of the doe-eyed youths on the verge of tears in Mr. Calvin bear a striking resemblance to Mr. Katz’s portraits of his son, Vincent, as a youth. The sentimental multiracialism of “Broad Daylight” (2004) depicting crossed white fingers tilting in the direction of a sole black finger, on the surface may look more like late Philip Guston. But with the young Vincent in mind, there seems to be more than a nod towards “Vincent and Tony” (1969), a double portrait, in the Art Institute of Chicago, of the young Katz with an equally doleful looking African-American pal.

Influence and acknowledgement aside, the real connection between protege and mentor is that closer looking turns up the painterly depths that willful simplification and knowing naivite would seem to have eschewed.

While Mr. Calvin’s portraits seem to be rendered vacuously from observation of particular people, the British painter James Rielly works the other way around: He gives specificity to what start life as generic, illustrative figures. Less a diaristic account of personal adolescence, his paintings extract something vaguely sinister from childhood, fusing nursery colors and design with intimations of alienation, even abuse.