Kjell Sandved, a nature photographer for the Smithsonian Institution’s Museum of Natural History, at work in a pond. (Frank Greenwell)

Kjell Sandved, a Norwegian publisher who found a second career as a nature photographer for the Smithsonian Institution, capturing closely observed images of butterflies, plants and other forms of life, which he published in a series of books, died Dec. 20 at his home in Washington. He was 93.

He had dementia, said Barbara Badian, a friend and business associate.

Mr. Sandved, whose first name was pronounced “Shell,” was a man of singular vision who never did things by half-measure. After compiling and publishing two single-volume encyclopedias on music and art — each more than 1,000 pages in length — he set about compiling another encyclopedia devoted to the natural world.

He was at the Smithsonian’s Museum of Natural History in 1960, looking through a cigar box containing a collection of butterflies, when he noticed the letter “F” in the wing of one specimen. He took a photograph, put it above his desk and soon became consumed with curiosity.

“Not even a calligrapher could have improved on its beauty,” Mr. Sandved later wrote. “My mind was made up. I was going to search for the entire alphabet.”

Facelike markings on a butterfly wing. (© Kjell Sandved/ )

And so began a decades-long search, as he wondered what else he might see in the wing patterns of the nearly 20,000 species of butterflies across the globe.

Abandoning plans for a comprehensive encyclopedia on nature, Mr. Sandved stayed in Washington as a volunteer at the museum. He redirected his career toward nature photography, teaching himself the craft by trial and error.

“Before I came here, I really wasn’t interested in photography,” he told a Smithsonian employee publication in the 1980s. “Why, I didn’t even know how to use a camera!”

After two years, he was hired to help assemble and photograph exhibits. Two years after that, Mr. Sandved became the Museum of Natural History’s first full-time nature photographer. For nearly three decades, he traveled the world for the museum.

“He has old friends everywhere,” a 1987 Smithsonian magazine article noted. “Walk down a street with him in Anchorage, or Tokyo, or Oslo, or Des Moines, and someone is sure to wave and shout, ‘Hi, Kjell!’ ”

He visited more than 30 countries, climbing across ice fields, walking through deserts and crawling on jungle floors to capture such diverse forms of life as piranhas in the Amazon, penguins in Antarctica and white tigers in India.

Mr. Sandved worked alongside the country’s leading researchers on insects, plants and marine life. He photographed archaeological excavations in the Middle East, coral reefs in the Pacific and the world’s largest flower, the three-foot-wide Rafflesia arnoldii, in Sumatra. Once, while photographing orchids, he looked down and saw a viper inches from his face. It was perfectly formed in the shape of the letter Q, and Mr. Sandved got his photo before stepping away from danger.

Yet, through it all, his overarching interest remained the delicate world of butterflies and moths. He devised ways to take pictures through microscopes and built other equipment from spare parts, including specialized lights and underwater platforms.

He became an authority on all things lepidopterous and spent thousands of hours in the field hoping to capture the beauty of butterflies with his cameras. It was best to go out early in the morning, and he learned to approach them slowly, walking straight ahead. Any lateral movement would drive them away. He was proud that he never killed or damaged a butterfly in his many years of photographing them.

In 1975, Mr. Sandved produced his first “Butterfly Alphabet” poster, with all 26 letters — and the numbers 1 through 9 — represented in the varied hues of butterfly wings. Over the years, more than 1 million copies were sold.

From 1973 to 2004, Mr. Sandved published nine books of nature photography, including four on butterflies and others on shells, rain forests, leaves and tree bark. During his years at the Smithsonian, he also produced many educational films on nature and animal behavior.

“Nothing is more important,” he said in 1999, “than to teach children that nature is not something that should be trampled on, uprooted or cleared for cement buildings.”

Kjell Bloch Sandved was born Oct. 20, 1922, in Strandebarm, Norway. He was 4 when his father, a doctor, died. After his mother remarried, the family moved to a town not far from Oslo.

Mr. Sandved studied electrical engineering at the University of Oslo and became fluent in six languages. He founded a publishing house in 1948, the year his first book, “The World of Music,” appeared. Seven years later, he published “The World of Art.”

The books had exceptionally high production standards, with elaborate illustrations, burnished leather bindings and covers made with a veneer of African mahogany. He lived for years off the royalties of the books, which were translated into several languages.

During his tenure at the Smithsonian, Mr. Sandved lectured widely on animal behavior. He was featured in a 1983 Smithsonian documentary, and for many years he traveled around the country as part of the Smithsonian Associates program, showing his photographs and films. He retired in 1992.

Mr. Sandved’s work has been displayed at the Museum of Natural History and other museums and has appeared in many publications, including Smithsonian and National Geographic magazines. The Dixie Chicks used his photography for the cover art of “Fly,” their 1999 album.

Mr. Sandved never married and had no immediate survivors. In later years, he launched a company, Butterfly Alphabet, that distributes butterfly posters, cards and related items. For years, he had been at work on a book of photographs of spiders.

“Most people have no idea how many beautiful things are out there for them to see,” Mr. Sandved told Maine’s Bangor Daily News in 2005. “There is a line in a Theodore Roethke poem that says, ‘All finite things reveal infinitude.’ Those are words to live by.”