all images courtesy of Beatrice Thornton

Slightly more than 3 miles long, California’s Sausal Creek originates in the Oakland hills and flows on a fairly straight course toward the Oakland estuary. For centuries, Indigenous Ohlone tribes and their descendants have been gathering seeds and berries along its willowed banks. But today, walking along the Sausal on a sunny May afternoon, photographer Beatrice Thornton is foraging for darkroom chemicals.

“I love how this trail changes every day,” she says, stopping to admire a blooming nasturtium. “I really notice the life cycles of plants: what’s in season, what’s going to be in season.”

Thornton is a slender, athletic woman, articulate and thoughtful. In many ways, this creek has been her muse. “When I was younger, I never paid much attention to the species of plants. It was all just stuff that grew there. But having the chance to go on this trail every day, I’ve been learning much more about the history of the area. I’m much more conscious of what is native and what is invasive.”

Today, Beatrice is on the lookout for elderberry. Aside from making a good cordial, it’s rich in polyphenols: an antioxidant compound found in all plants. These antioxidants can be used—in combination with vitamin C, super washing soda, and even coffee—to develop negatives and prints in her plant-based craft of “analog” photography.

“What sets analog apart from digital photography,” she says, “is that in a digital camera, you have a code that is stored. It doesn’t look like the thing being photographed.” But just as an analog record has grooves that physically capture the recorded sound, the coating on film and photographic printing paper—which is made of light-sensitive silver salts suspended in gelatin—physically captures and holds the image.

During the first spell of photography, in the mid-19th century, William Henry Fox Talbot—the British “father of modern photography”—used plant-based extractions. But advances in the new art form soon gave way to mass-produced chemical developers like Dektol, a possible mutagen that can cause skin problems and eye damage.

“So this isn’t necessarily a new process, explains Thornton. “It’s just that the chemistry that everyone knows about today is toxic.”

When we return to her home, walking distance from the Sausal Creek, I see a pot of broad leaves, collected previously, simmering on the stove. “Those are loquat leaves,” she says, “which you can also use as a tea.”

She drops today’s harvest into the sink. “So here are the stages. We just were out foraging; I got this stuff here. I’ll tear it up and boil the plant in water for a few minutes, then let it steep for however long; as little as a couple hours, or overnight sometimes.” The other ingredients she’ll add—super washing soda and Vitamin C—wait on a nearby counter. For a “stop bath” (which halts the developing process) Beatrice simply uses water, followed by Eco Pro fixer, “although a salt solution can work as well.” While used developer can be poured down the sink after a single use, Beatrice recycles exhausted fixer as toxic waste. “Because it contains silver, I do not dump fixer down the drain.”

I wish I could say there was a component of sorcery to her brewing, but the process looks as innocuous as preparing eggs Benedict. The enchantment in her work, I learn, comes not so much from the developing process itself as in the relationship between her foraging and her photographs.

“Medicinally, I’ve learned that loquat leaves are good for the skin. Also, the tea is very calming. So, thinking about the conceptual parallels between process and imagery, maybe I’ve shot some images that I feel are very serene and calm. Using loquat leaves as the developer adds meaning to that—even if the leaves are not visible in the image.”

These circular projects are central to Beatrice’s craft, in which subject, image, and chemistry are interwoven. She describes an afternoon of weeding she did with the Friends of the Sausal Creek. Volunteers met at a native plant nursery they maintain in a nearby park. Throughout the afternoon, Beatrice photographed her surroundings: piles of weeds, the landscape, and the nursery itself. She also shot some double exposures.

“At the end of the day, I took some of the weeds home. A lot of that was wild radish. Then I made the plant brews.” Beatrice developed her images using the very weeds she’d collected and photographed that afternoon.

I wondered if using wild radish—which often has colorful yellow, white, or pink flowers—influenced the way the printed image turned out. This is a question, she says, that often comes up in her workshops.

“When I tell people that I develop with plants, some of them assume there is going to be some remnant of the plant or the flower; some color variation. And yeah, sometimes it does stain the film—but that’s actually not ideal, to get a green or yellow stain. I mean, it looks kind of cool, but it also makes it a little more difficult to print.”

What you really want, Thornton says, is “to get a result that looks as close to traditionally processed film as possible. And using the chemistry in some plants—in good ratios with the other natural ingredients—gives results that can be indistinguishable from toxic developers.”

Some of her recent work includes photographic collages, for which she overlaps different negatives on the same sheet of photo paper. She showed some of the double exposures—all developed with site-specific plant developers—at a 2023 exhibition called “Place Non Place” at the Lakeview branch of Oakland Public Library.

“When they were strung together, the photographs become an imagined panorama, of a place that does not exist. But individually, they’re all real places. I was playing with idea of places, real and imagined.”

Though Beatrice is devoted to crafting plant-based developers, she remains passionate about the crisp results of the gelatin silver process: the traditional way of developing film. “But I have a lot of problems with it, because you’re still using plastic, and you’re still using silver. And though I’m making sustainable developers, I’m still buying film, which has new silver in it. So there’s the whole supply chain thing.”

“My hope is that in the next five years, there will be improvements in bioplastics for making films, along with easier and more accessible ways to recycle silver—so that sustainable darkroom practices will be even more sustainable.”