Camille Pissarro's drawings -- now on exhibition at Franz Bader's Gallery, 2001 I St. NW -- are wholly unpretentious. The man was like that, too. He hated insincerity. He shunned the chic, he battled for the new, and he could tell the difference. Perhaps it is no wonder that so many masters -- Ce'zanne, Gauguin, Degas, van Gogh -- viewed him with respect. And with deep affection.

Vincent van Gogh often asked his beloved brother, Theo, to say hello to "old Pissarro." Monet loved him too and in 1892 lent Pissarro the money to buy a house. "He was such a teacher," said Mary Cassatt, "that he could have taught stones to draw correctly."

Pissarro's lack of trickery, the intensity of his seeing, and his easy generosity endeared him to Ce'zanne, who called him "humble and colossal." A small and open Pissarro landscape of 1852 shows how much Ce'zanne would learn from the older painter. Nor did Ce'zanne conceal that debt. In 1906, with Pissarro already three years dead, Ce'zanne described himself in print as "Ce'zanne, pupil of Pissarro."

Gauguin learned from Pissarro, too. When Gauguin described himself as "an Impressionist, that is to say a rebel," he was remembering Pissarro, who had so long been both. Pissarro, as a young man, had left the bright lights of the city to paint in Brittany. Gauguin, van Gogh, Matisse and many other younger men would later do the same.

Gauguin was a haughty man. He could not acknowledge debts with ease. Yet he spoke up for his teacher. When some younger Paris painters scorned Pissarro's landscapes as tediously old-fashioned, Gauguin, uncharacteristically, rose to the defense: "They deny him now, but I shall not. He was one of my masters."

This pleasant little show allows us to revisit one of the great chapters in the history of painting. Pissarro (1830-1903) linked the age of Corot with that of Picasso. He showed in all eight of the Impressionist exhibitions. He was Impressionism's grand old man. And he looked the part.

His eyes were dark and kindly. His beard was long, untrimmed and white. To Ce'zanne he looked like God.

Pissarro was throughout his life a bit of an outsider. A Jew born in St. Thomas in the Danish West Indies, he was never quite at home in fashionable Paris. And his politics were firm. He was a painter of the left. We see that in these sketches. Unlike, say, Degas, Pissarro did not portray the rich, the gamblers of the Jockey Club or the sleek young men in evening clothes who chatted up the dancers of the opera. He preferred to paint the peasants. They bend to weed their gardens, they lead their cows to pasture, they thresh their grain or lean, exhausted, on their shovels throughout the drawings in Bader's show.

Pissarro could not bear the prissy or the glib. "I have the temperament of a peasant," he wrote. "I am melancholy, coarse and savage in my work." You sense that in these drawings. Whether thinking about light (see the way he studies the glare of winter snow or the sheen on a silk hat) or pondering the backbreaking labors of the peasantry, he always shows us simply, honestly, precisely what he sees.

A year ago Franz Bader acquired a group of Edouard Vuillard drawings from a London dealer with links to Vuillard's estate. These 32 Pissarros -- priced at $1,550 to $75,000 -- come from the same source. Few qualify as major works. Most have been "signed" with a rubber stamp, not by the artist, but, rather, at the direction of his heirs. They're modest pictures. Their very modesty evokes Pissarro's spirit. They'll be on view until April 13. Paintings by Theodor Pistek

A show of Theodor Pistek's ambiguous, amusing, surrealistic paintings goes on view today at Henri's, 1500 21st St. NW. His timing is terrific. Last Monday night a few hundred million people saw Pistek -- who designed the costumes for "Amadeus" -- win an Academy Award.

Pistek, a Czech, has been the designer for more than 100 movies, and some trace of that experience -- something accurate and high-tech yet magical as a vaudeville show -- is apparent in his art.

The painting he calls "The Box" shows an immaculate container, enameled, trimmed with chrome. It might house a computer. But it doesn't. Out of it leaks trash -- cigarette butts, burnt matches, used razor blades, bent nails. The painting that he calls "The Door" begins as a landscape. Green grasses grow beside a pond, water glistens in the sun. But the canvas has been slashed -- or, rather, it's been painted so that it looks slashed -- and through the slash we see the dials and red lights of some complex machine.

Movies look real, but aren't. Pistek's paintings also contradict themselves. For my taste, they seem a little tricky. Pistek admires Dali. His "Self-Portrait With a Colleague" shows a paper-wrapped severed head on a kitchen chair. A portrait of the Spaniard looks down from the wall.

Though his brushwork is meticulous, and his style international, there are a hundred gifted illustrators in a dozen countries who can paint as well as he. Still, this show is entertaining. It was arranged through the good offices of Washington's Meda Mladek, that untiring champion of contemporary Czech art. It runs through April 24. Aboriginal Paintings

The Martin Gallery, 3243 P St. NW., is showing aboriginal paintings from the far north of Australia. They're new, but they feel timeless. They are painted on bark. Their colors are but ochres and rare earths. Their artists use chewed twigs, not brushes.

Archeologists believe that in technique -- and in message -- Australian painting has changed little in 40,000 years. This is not art made for art's sake, but a method for communicating totems, legends, myths.

The artist Nguleingulei of the Gunwinggu paints in the X-ray style. When he depicts a kangaroo, he shows its intestines, backbone, lungs. Nearby hangs a picture by Johnny Bulu-Bulun that seems, at first glimpse, an allover abstraction. But amidst its dots and cross-hatchings lurk many long-necked tortoises. Other unfamiliar creatures -- anteaters, flightless birds, flying foxes, and rainbow spirits -- are portrayed in this show. It closes April 6. Jonathan Shahn

Jonathan Shahn, whose drawings and sculptures are at the Addison/Ripley Gallery, behind the Phillips Collection at 9 Hillyer Ct. NW., is an admirable artist. He is intelligent, inventive. Throughout his show one senses that the boundaries between sculpture and drawing, and sculpture and painting, have somehow been erased.

The sculptures of the Greeks were not chaste marble. They were painted with great care. Shahn has in his own way reinvented that technique. When he carves of oak a colossal seated figure, or assembles out of bits of spruce a life-size standing figure, he does not leave the stripped wood bare. He draws on it with paint, adding with a few quick strokes an eyebrow or a collarbone or a fold of flesh. One of his large busts of oak -- which portrays a pensive man with his chin in his hand -- has been daubed with red and white and black, and then encased in wax, which gives the wood the look of flesh.

All his works are portraits. None are generalized figures. Whether carving a bust or assembling a statue, whether making terra-cotta plaques or prints or charcoal drawings, Shahn produces individuals. The late Ben Shahn, the artist's father, is seen in bronze, reclining, reading the newspaper. Jeb, the artist's wife, and Jasper, their young son, also are portrayed here. This art is never forced. Shahn's figures feel alive. His show closes April 27.