SIGMAR POLKE'S tall artworks which cover a wall with shifting colors are a looming presence, like Gibraltar or the Black Slab in Kubrick's "200l" or flying into a bank of storm clouds. Yhey are part of a mysterious series by the German-born artist included in the show on view through May 5 at the Hirshhorn Museum and Sculpture Garden. They are grouped under the title "The Spirits That Lend Strength Are Invisible." One painting has a subtitle: "Tellurium Terrestrial Material" because it's made of pure tellurium, a semimetallic element related to selenium and sulfur. In this case, pure tellurium is blown onto artificial resin on a huge canvas, 157 in. by 118 1/2 in.
The resulting art is enormous, shiny, glistening, and extremely hard looking, like armor. The second in the series, a whirl of golds and yellows contains one kilogram of a meteor (extraterrestrial material found west of Tocopilla, Chile), thrown onto artificial resin.
The third contains layers of nickel in artificial resin; silver nitrate is used in the fourth, subtitled "Salt of Silver" and the fifth subtitled "Otter Creek," includes silver leaf, neolithic tools, and artificial resin on canvas. You can see the neolithic tools, which look like metallic arrow heads, embedded in the painting.
The overall effect of the five large "alchemic" works, which could be unearthly abstract expressionist paintings, is inexplicable. The artificial resin used has a golden sheen, which lights up the paintings as you move around them. And the appearance of the works shifts according to temperature and humidity, like a "mood" ring.
"The Spirits That Lend Strength Are Invisible" series title was based on a Native American proverb. The show's organizer, John Caldwell, curator of painting and sculpture at the San Francisco Museum of Modern Art, says in the catalog that "The whole suite is an homage to and meditation on the Americas because it utilizes for its creation only materials associated with the New World as opposed to Europe."
He also calls it "a culmination of his work to date 201&gt; a series of five paintings [Polke] made for the 1988 Carnegie International exhibition in Pittsburgh...."
More than l00 of Polke's paintings, works on paper and special art works are included in the show, his first full retrospective in the United States. Polke's influence on other artists is significant, but he is better known in Europe.
Another unforgettable series, which illustrates Polke's melding of social consciousness with art is the haunting "Watchtower" grouping. Again, the works of art are huge ("Watchtower with Geese") is 114 3/16 inches square).
Polke's high, spindly, sinister watchtower has a cumulative effect in series, like Monet's haystacks or Rouen cathedrals or Cezanne's Chateau Noirs.
While this series is compelling, it is also grim, full of the tragedy of the Nazi concentration camps.
This is most evident in Watchtower 11, done in silver, silver oxide, and artificial resin on canvas - the watchtower seen through a murky half-light. But Polke seems to treat it as gallows humor in "Watchtower with Geese" which juxtaposes the watchtower symbol with fabric on which a gaggle of geese waddles.
But the surrealistic horror of his concentration camp images comes through most clearly in his earlier "Lager" (Camp), which comes at you like an enormous freight train, 14 feet high and eight feet wide.
The bottom third of the work is a powerful charge of diabolic blackness, bounded on either side and above with walls of razored barbed wire and black lights. Horizontal lashes of purple lines are superimposed over the metallic gold sunset which forms the top third of the work.
It is an unforgettable image of acrylic and spattered pigment on fabric and blanket. Burned into the blanket at intervals are grotesque holes which reveal glimpses of the white walls behind in light and shadow. The blanket humanizes the painting, which is the view seen by inmates of the camp.
Mr. Caldwell suggests in the show's catalog that the watchtower series could also symbolize the towers which until recently guarded the boundary between East and West Germany.
Polke was born in Oels, in Silesia, which was then the eastern part of Germany. At the age of 12, in 1953, he simply got on a subway going to West Berlin, pretended to be asleep, and crossed safely to the West.
He grew up in a post-war Germany that was often deprived of food. Later he painted pop art images of doughnuts, bread, and a chocolate bar.
By the 60's, American Pop Art figures like Andy Warhol and Roy Lichtenstein had crossed his horizon.
He briefly studied the art of glass painting, then had enrolled in the Art Academy in D 159&gt;sseldorf, where he and artists Gerhard Richter and Konrad Fischer-Lueg began painting in a style they called "Capitalist Realism," a pun on the Socialist Realism of Germany.
He then went through a period of zapping the art and culture of his times with satirical paintings of several styles, including Color-Field paintings, conceptual art, and even incorporating decorator fabrics into his paintings.
Polke's humor pops out in a vast acrylic on canvas called "Peruke" - a woman in a powdered wig so mountainous that birds fly in and out of it.
Powerful is the only word that describes some of Polke's other paintings - layer on layer of images, often on fabric. Walking into a room full of them, you feel you need a translation to understand.
Can one get the picture? It's a bit difficult because, according to Caldwell, these paintings are "a depiction of the distortions of reality that might be induced by ingesting psychedelic substances."
There is, for instance, "Alice in Wonderland," done in mixed media on fabric strips. One strip is of basketball players on a green court, another of blue and black polka dots with images of Alice with caterpillar, hookah pipe, and magic mushrooms superimposed on them.
About that painting, Caldwell says "the theme of drug-altered consciousness is explicit. One of the later ones is titled "Hallucinogen" in layers of violet, bronze, and black oil on canvas. After this period, Polke turned to his major series, "Watchtower" and "The Spirits That Lend Strength Are Invisible."
This exhibition of the work of Sigmar Polke, who is now living in Cologne, Germany, is touring the US. After closing at the Hirshhorn, the show will go to the Museum of Contemporary Art in Chicago (June 20-Sept. 8); then the Brooklyn Museum (Oct. 11, 1991-Jan. 6, 1992.