Can portraiture be iconic without being illuminating? Can photography conceal as much as it discloses? Can style overpower substance? And can celebrity hold our attention long after an image falters? The answer to these questions, which is yes, can be found over and over again in “Close Encounters: Irving Penn Portraits of Artists and Writers,” a beautifully installed exhibition of 67 portrait photographs that opens tomorrow at the Morgan Library & Museum.

The innovative and accomplished American photographer Irving Penn, who will turn 90 in June, does what he does very well. His images have drama, grace, and panache. But, as this exhibition — as alluring as it is wearisome — proves, a little of Mr. Penn’s overdetermined style goes a long way. Although he has produced spare, crystalline fashion photography that has contributed to some of the most elegant magazine covers and spreads of our era (especially the mid-century work he did for Vogue under the direction of his mentor Alexander Liberman), Mr. Penn’s images are best seen alongside the essays they accompany on the pages of the magazines that commissioned them. As works in and of themselves, his portraits tend to leave his subjects out in the cold.

“Close Encounters,” guest curated by Peter Barberie, represents the first modern photography exhibition at the Morgan, as well as its first major acquisition of the medium. Arranged chronologically, and spanning Mr. Penn’s entire career as a portrait photographer, the show comprises pictures, taken mainly for Vogue but also for the New Yorker, that he shot between 1944 and 2006. Mr. Penn donated 35 of the photographs to the Morgan in 2007. The remaining 32 were purchased directly from him. This, however, is not the first major donation by the artist. A few years ago, Mr. Penn gave more than 100 images to Washington’s National Gallery of Art. With the recent museum gifts of these rich, hyper-velvety and silvery images — a number of which, blown up, have been meticulously reprinted by Mr. Penn — it appears that he is attempting to secure his position as a celebrated artist, above that of a celebrated fashion photographer.

Initially gripping, Mr. Penn’s pared-down, shadowy portraits at first appear glamorous and mysterious, yet honest and unassuming. His 1946 portrait of John Cage has the composer tuning a piano, as if he were a mechanic under the hood of a car. A backlit image of Aaron Copland at the piano, also from 1946, is almost pure silhouette, with the sheet music fluttering like the wings of a bird. A bulbous portrait of David Smith, taken in 1962, is frank. Looking up at the sculptor, who is sucking on a pipe, its focus is on Smith’s gnarled thumbnail. And some of the portraits are so familiar and ubiquitous, so much a part of our culture, that they may be among the first mental images at the mention of their sitters. However, Mr. Penn’s subjects — as if seen through the eye of an entomologist rather than through that of a portraitist — can look as if they are under a microscope.

Mr. Penn, who generally shoots his portraits in the controlled, relatively bare environment of his studio, treats his sitters more as specimens to be examined than as individuals to be explored — a dynamic that seems to force them to close down and to pose themselves into protective guises and predictable types.

At the Morgan, individual genius and personality are sometimes trumped by the grandeur of style. In photographs of people as diverse as W.H. Auden, Alexander Calder, T.S. Eliot, Carson McCullers, Philip Roth, and Tennessee Williams, we encounter recurring categories as much as we do individuals. Mr. Penn’s subjects are defensive, reclusive, pensive, brooding, aggressive, innocent, questioning, or childlike. And then there is the standby: A number of sitters, including Simone de Beauvoir, shot in Paris in 1957, appear to have resorted to the intent stare — a mask that has come to represent the misunderstood seriousness of artistic genius. Some of his subjects can even look as if they are cornered animals waiting for the kill — the click of the shutter.

A 2002 reprint of an original 1957 portrait of Picasso is the first image you encounter at the Morgan. Closely cropped and blown up to poster scale, it is a classic if not iconic portrait of the Spaniard who, seemingly starkly arrested, peers from out of deep shadow. Half of Picasso’s face is completely dark.

The brim of his wide fedora is a graceful gray curve. His nose is prominently lit, and his mouth, chin, and cheek are buried in his matador’s cape. It is Picasso’s piercing eye, resolute but also on guard, however, that is at the center and is the subject of the image. Although the portrait is much too large, it is a beautiful photograph. Mr. Penn, rather than draw Picasso out, appears to have forced the artist into hiding.

The Morgan’s portraits can appear to line the walls like trophy heads. Jasper Johns looks like a baboon attempting to stare us down; Louise Bourgeois, her hands clasped and her eyes shut, is closed off — as if in mourning or in prayer; Ingmar Bergman, as if accepting his fate, has just used his fingers to close his eyes; Truman Capote has rolled himself childishly into a ball, and many of Mr. Penn’s subjects (beginning in 1948, the photographer had his sitters position themselves in a narrow, vise-like corner) look as though they have absolutely nowhere to run.

This is not to suggest that there are not some wonderfully engaging pictures in the mix. I was mesmerized by a portrait of Jean Cocteau, as well as by “Ballet Society” (1948), a group photograph in which principal dancer Tanaquil Le Clercq stands like a goddess, as three seated men, Balanchine among them, are heaped at her feet on the floor. And most of the images on view have the power to hold us simply because of the charisma of their sitters. But too often, the portraits rely on devices — cropping, the studio corner, theatrical lighting, or a seemingly adversarial lens, for example — to contrived, overly dramatic effect.

An exhibition this large tells us more about Mr. Penn’s approach to portraiture than it does his subjects. And there are much better — more penetrating and illuminating — portraits out there of the same subjects tackled by Mr. Penn: They include Balthus’s paintings of André Derain and of Joan Miró and his daughter, Dolores, Alfred Stieglitz’s photographs of Georgia O’Keeffe, the image of Ingmar Bergman talking with Death on the set of “The Seventh Seal,” as well as certain portrait photographs of Giacometti in the studio, all of which eclipse Mr. Penn’s achievements. Mr. Penn’s well-crafted photographs may occasionally rise to the level of genuine art, but they rarely transcend fashion photography to become genuine portraiture.

January 18 through April 13 (225 Madison Ave., between 36th and 37th streets, 212-685-0008).