Using intricately arranged lenses, prisms and mirrors to direct light from lasers or the sun, Mr. Krebs pioneered what he called, in one of his exhibitions, “sculpture minus object.”
He began on a small scale, using lasers reflected in mirrors inside a room at a Washington art gallery in 1968. He soon expanded to large outdoor installations, with light beams that danced off buildings and sometimes extended for miles.
By 1971, Mr. Krebs had designed an installation of reflected light at the World’s Fair in Osaka, Japan, displayed alongside works by such renowned artists as Claes Odenburg, Roy Lichtenstein and Andy Warhol.
“Krebs is one of the most inventive artists working in Washington today,” Washington Post art critic Paul Richard wrote in 1971. “Krebs alone, of all our artists, has managed to transcend the look of the synthetic.”
His light sculptures were known for their clarity of form and for giving the illusion of confined or infinite space. Mr. Krebs was one of the few artists of the time to use the power of light as a primary artistic palette.
He devised one of his most dramatic light sculptures, called “The Source,” in Washington in 1980. He spent months getting approval from various federal and local agencies, airport authorities and the Secret Service before he could direct parallel beams of argon and krytpon lasers from the Lincoln Memorial across the Mall.
One beam floated above the White House and extended three miles up 16th Street NW. Another beam, striking a strategically placed mirror, abruptly turned at a right angle and passed over the Mall until it disappeared in a grove of trees near the Capitol.
“His works of art are peculiarly at peace with the visual confusion and the scale of the city,” Richard wrote in The Post at the time. “They deal with whole landscapes, they put color into space, and they lend a sense of order to the chaos of the night.”
Rockne Krebs was born Dec. 24, 1938, in Kansas City, Mo., and was the son of an electrician. After graduating from the University of Kansas in 1961, he moved to Washington while serving in the Navy.
He was struck at once by the vibrant paintings of the Washington Color School
of artists, said California curator Jay Belloli, who worked with Mr. Krebs on several projects and is writing a book about his art.
Influenced by the the boldly striped paintings of Gene Davis and the vivid chevrons of Kenneth Noland, Mr. Krebs took bright colors from the flat surface of a canvas and placed them directly in the physical environment.
He created cat’s cradles of bouncing and intersecting threads of colored light. To create other illusionistic effects, he used a camera obscura to project outdoor scenes onto the interior walls of rooms.
In 1969, Mr. Krebs began working with engineers at Hewlett-Packard in California to develop new ways of using light in his environmental sculptures. In one ambitious project, he sent lasers from an observatory on California’s Mount Wilson to the campus of Caltech, eight miles away. For an installation in St. Petersburg, Fla., he beamed lasers out into the Gulf of Mexico, where a ship captain saw them 36 miles from shore.
After studying patterns of sunlight in Atlanta, Mr. Krebs created an arrangement of prisms in 1976 that would show a human eye. The image, modeled after his daughter Heather’s eye, was visible only two days a year, on the spring and autumn equinoxes.
Mr. Krebs’s laser methods had few precedents in art, but they have been widely copied at rock concerts and other spectacles. In later years, Mr. Krebs created works with lasers and neon in Louisiana, California, Indiana and Pennsylvania. He also designed a permanent installation, using sunlight and prisms, at the Children’s Inn of the National Institutes of Health.
His marriages to Denise D’Agostino, Marguerite Gordon and sculptor Nizette Brennan ended in divorce.
Survivors include a daughter from his first marriage, Heather Krebs of Washington; two children from his third marriage, Rockne B. Krebs and Nizette C. “ZZ” Krebs, both of San Diego; his mother, Lorine L. Krebs of Blue Springs, Mo.; and two brothers.
Mr. Krebs received commissions for his work and fellowships from the National Endowment for the Arts and the Guggenheim Foundation. Yet for all his critical success, he told The Post in 1977, “I often found myself absolutely broke.”
“Of the 38 major pieces I’ve made in the last 10 years, two still exist,” he said. “Perhaps I ought to start making still-lifes of flowers.”