The refrigerator in the home of Josie Iselin ’80 sometimes contains specimens of fresh seaweed, waiting for its close-up in Josie’s photography studio. “My family feels funny about it,” Josie admits, but keeping the newly harvested marine algae cool is one key step in a unique process she used to create the images for her latest book, An Ocean Garden: The Secret Life of Seaweed (Abrams, 2014).

Though trained as a photographer, Josie did not need a camera to capture the striking and contemplative seaweed shots that fill the pages of her book. Instead, she used a flatbed scanner, a method she has employed for about two decades. Specimens were placed on the scanner’s glass (which, she points out, is insoluble), and if necessary, “helper stones” were used to prop open the lid and prevent squishing. Windex is always on-hand in her studio, Josie adds.

The idea for An Ocean Garden, Josie’s seventh book, came to her one day at the Duxbury Reef in Bolinas, near her home in San Francisco. “I found a piece of magenta seaweed, held it up to the sky, and was knocked out by the color and the form,” she recalls. At the time, she was doing research for her previous book, Beach: A Book of Treasure (Chronicle Books, 2010), and was training to be a docent at the reef.

The moment with the magenta seaweed led to more scientific research, including time spent at the University Herbarium at UC Berkeley, which cares for what Josie calls the “foremost collection of seaweed on the West Coast.” Some of the scans in An Ocean Garden (the end papers, for example) are of pressings from that collection dating back to the 1880s and 1890s. Nonetheless, Josie explains, the study of seaweed is a relatively new science. Current practice includes efforts to “geo-locate where all specimens are from, so with global warming and oceans warming, they can see how species might migrate north.”

Josie’s interest in ocean life comes not only from artistic and ecological standpoints, but from a deep personal connection to the shore. “I’m very much of a bicoastal ocean person,” she says, pointing out that when she was growing up in New York, her parents bought a house in Vinalhaven, ME, where she and her family now spend time each summer. The seaweed species in the book are concentrated on those from California and Maine.

The plant forms, she says, also evoke “the design aesthetic of my youth,” when she spent time at the Design Research store, admiring Marimekko fabrics. In fact, her interest in photography dates back to her time at Spence, when she took a sixth grade photography class with Lisa Sheble. “I can remember the cubby under the stairs where you rolled the film,” she recalls warmly, noting that in that class she learned alternative processes such as silk screening, and gained an appreciation for experimentation.

Ms. Sheble later photographed Josie’s wedding in 1991, and the two recently reconnected after Ms. Sheble saw the review of An Ocean Garden in The New York Times—one of several notable media outlets to cover the book.

“The feedback I’ve gotten has been much more enthusiastic than I’ve expected,” Josie says of the response. “Seaweed has come a long way.”

Find additional information on Josie’s website.