THEY WERE another race.

In the worst days of the Depression, people could stare at those perfect faces--shadowed and sleek and enigmatic, languidly looking out forever from the slick paper--and be miraculously, instantly transfigured into a world of silence where it never rained and no one ever moved and beauty was the day and the night.

An absolutely stunning show of Hollywood portraits has just opened at the National Portrait Gallery, 110 lush photographs that will remain up through March 27. It is more than a show--just as the book behind it, John Kobal's "The Art of the Great Hollywood Portrait Photographers"--is more than a coffee table confection. It is a statement about Hollywood, about America, about dreams.

Our ideal was to make a totally idealized, larger-than-life figure of the stars on which the whole system was built. Who they are, what they were didn't really matter. --Photographer Laszlo Willinger

It is the skin you notice first. Luminous, sculpted, its sexual curves and hollows so delicately shaded that your very fingers are beguiled into believing they can feel it. Many of the women wear satin to bring a glow to their skin, but it is the lighting that really creates the effect.

Light! These people are made of light.

Years ago, the great Edward Steichen took thousands of pictures of a plain white cup and saucer to learn everything there was to learn about lighting a subject. The master Hollywood photographers, Ernest Bachrach, George Hurrell, Ted Allan, Ruth Harriet Louise and the others, seem to have started where he left off.

"For the sake of an interesting photograph," writes Kobal, "Dietrich thought nothing of leaning over a chair, unsupported in a backbreaking position, for minutes on end while von Sternberg explored her face with lights--a high spot to bring out the shadows under her cheekbones, another to shade very slightly the top of her forehead in order to round out her face . . ."

And in a caption under a Marlene Dietrich portrait engineered by famed director Josef von Sternberg, the man some called her Svengali: "Her cheekbones are great wide plains, and her eyebrows have been redesigned to create a larger space between eye and brow . . . Note her hands trailing off into the shadows. Though her fingers are actually short and stubby, they are posed to give the illusion of being long and sinuous."

And this is the point: The Hollywood dream people were, after all, human beings, creatures of the Third Planet just like the rest of us. To become the icons they were, they had to be transformed. Stars are made, not born.

Jean Harlow had a deeply cleft chin, a too-high forehead, almost a dish-face. Rita Hayworth's hairline was extremely low; she seemed to have almost no forehead at all. Norma Shearer's eyes were much too close together. Joan Crawford had a billion freckles and pop eyes. Robert Taylor looked so effete he was sent to a gymnasium to have his shoulders built up. (Eventually he became a first-rate horseman.) James Cagney's best feature, his piercing gaze, couldn't be seen in the middle distance.

But in the pictures, all that is changed. Harlow is seen from above, Shearer from the side. Hayworth had her forehead plucked. Crawford got a powder job. Taylor was photographed in roughneck clothes, scowling if possible. Cagney redesigned his eyebrows and used eye shadow to focus attention on his magnetic stare. It was more than cosmetics; it was a triumph of floodlighting, backlighting, highlighting, plus endless experimentation with poses.

Photographers and their cunning, unseen partners, the retouchers, could, as Kobal says, "straighten crooked teeth, clear eyes if they were dull or bloodshot . . . lengthen necks and eyelashes, whittle waists and excise ungainly pounds."

Rita Hayworth at 19, still pudgy with baby fat, stiff and uncertain, is simply not the same woman as Rita at 21, sleekly mature, mysteriously remote and exotic yet vibrant with sexual energy. The pictures were taken within two years by the same man, Whitey Schaefer, but they look 10 years apart. (She once said, sadly, speaking of her five husbands, that they all married the picture, ". . . but they woke up with me.")

Most important of all, the illusion depended on the abstraction of black-and-white, which permitted the faces to be seen as functions of light. When color came in, the faces were still beautiful, but it wasn't the same. They lacked that dream quality. They were too real.

I never paid much attention to the glamour bit. Dietrich is Glamour! The Queen. Like Crawford. Like Garbo was, still is . . . None of us girls--Lana, Rita, Dorothy Lamour--we couldn't possibly touch it. --Ann Sheridan

Some stars were virtually the product of their still pictures and never got much further than that, not necessarily for lack of acting talent but because they could never surpass the perfection of their portraits. Sexy Veronica Lake of the peekaboo look (a smashing picture in the show) could hardly keep that wave of hair in just the right place all through a movie. Dorothy Lamour's early portraits showed a sweetness and innocence that were overlooked when she was repeatedly cast as a sultry seductress.

Sometimes the star succeeded in films, but in a different direction. Early stills of Katharine Hepburn show a heavy-breathing siren with gleaming lips--not at all the persona that came to light in "The Philadelphia Story," the Spencer Tracy pictures and the charming match with Humphrey Bogart in "The African Queen," which she handled by thinking of herself as Eleanor Roosevelt.

Early pictures of James Stewart show just another smooth face, before he found his career as The Kid Next Door. Errol Flynn looks all wrong without his grin and his bare chest. Olivia de Havilland, before "Gone With the Wind," appears in a conventional slinky shot quite unlike the Olivia we think we know. And the John Wayne of 1931, brooding and shadowed, looks uncannily like James Dean, no doubt to the horror of them both.

These were mistakes, perhaps, natural enough in bringing a new and unknown face before the public. Yet they prove, maybe even better than the immortal successes, how much the photographers manipulated--created!--those faces.

Louise Brooks said, "What people remember of those stars is not from films, but one essential photograph: Dietrich--heavy-lidded, sucked-in cheeks. Keaton--sad little boy. Crawford--staring self-admiration. Gable--smiling, darling. And when I think of Garbo I do not see her moving in any particular film. I see her staring mysteriously into the camera. No matter how many times I've seen her in films, that is how I always see her. She is a still picture--unchangeable."

Many stars hated the sessions, made scenes, deliberately spoiled shots, rejected one version after another ("How many pounds of negatives have you done today?" an MGM publicist once asked Laszlo Willinger). Garbo, "the face of the century," some said, would only be photographed in connection with a film she was making. From '34 to '39 there are almost no modern-dress portraits of her because she made only costume dramas in that period.

But a few of the stars understood exactly what was going on. They realized the photographers were literally inventing them for the moviegoers.

"There is Joan Crawford, again and again," Kobal says, "her passion for posing as compelling as it is apparent, the concentration of profoundly felt suffering in a few finely sculpted contours on her forehead."

And Hepburn. And Dietrich. "Marlene Dietrich, an individual unique in every way, knew how she would be lighted and how she would pose, far better than any photographer making a picture of her," said William Walling Jr., who specialized in her.

While the show is up, the National Portrait Gallery and the American Film Institute will run a vintage film series at the gallery and the AFI theater in the Kennedy Center, ranging from the 1934 "Cleopatra" with Claudette Colbert to Tyrone Power's "The Razor's Edge."

The dreams of a generation: how we wanted to look, who we wanted to be. Maybe there is a lesson for history in these enchanted faces. Do they tell us anything about America and where it thought it was going? Or do they simply exist, meaning only themselves, our collective imagination right there on paper, an instant from the past staring back at us?

We had faces then. --Gloria Swanson in "Sunset Boulevard"