Seaweed, dried and pressed into lifelike shapes and muted green and yellow hues, covered a table at the Cannon Beach Chamber of Commerce. Some strands were leafy, others long and thin.

At one end of the table, Alanna Kieffer, a marine biologist and seaweed farmer, and Sam Block, a woodworker and photographer, handed out pieces of light-sensitive paper to dozens of students, who were there to make cyanotypes out of the marine flora.

Cyanotype, Kieffer explained, is one of the oldest methods of photographic printing, in use since the 18th century and historically popular for botanicals, especially seaweed.

The prints, which are named for their distinctive blue or cyan color cast, are made using ultraviolet light and chemically coated paper.

They even appeared in the earliest book of photography ever made. “Photographs of British Algae” by botanical artist Anna Atkins, from 1843, made use of none other than seaweed. Cyanotype, Kieffer added, is also the root of the word “blueprint.”

After arranging our collages on cardboard sheets and transferring them onto paper — each participant got five sheets — it was their time in the sun. On a partly cloudy winter afternoon, exposures took between five and seven minutes. On a summer day, Kieffer warned, the light could work much faster.

After bringing the prints back inside, they were washed and left to dry on clothespins by a fireplace, then taken to new homes.