For most people, photographs are digital files that pop up on a screen, pictures you can copy, send, post and view with the touch of a finger.

But what if a photograph were an image bonded to a metal surface in a demanding process that resembles a chemistry experiment? Something that feels heavy in your hand, that you can hang on the wall, that your ancestors might be looking at 150 years from now?

That kind of photograph would be a tintype, one of the earliest forms of photography. While the technology had its heyday during the Civil War, it's now being resurrected by some young photographers looking to create something with more gravity than another cellphone selfie.

It's the specialty of Carla Alexandra Rodriguez, a 30-year-old artist who has been using the tintype technique to create evocative studio portraits and fine art images.

Rodriguez, who grew up in Houston, came to Minnesota to study photography at the Minneapolis College of Art and Design (MCAD). From the beginning, she was attracted to older, analog forms of photography that required chemicals and darkrooms.

"The harder it was to do, the more I liked it," she said.

One of the hardest and oldest technologies is tintype, a complicated and somewhat touchy technique invented in the mid-1800s.

Also called wet-plate photography, tintype involves coating a metal plate with collodion, a syrupy solution of cellulose nitrate dissolved in ether originally used to dress wounds. When the plate is dunked in a bath of silver nitrate, the surface becomes light-sensitive. The plate is then put into a holder and inserted into the back of a large-format camera.

The photo subject must be posed, the lighting set up and the camera has to be focused ahead of time because the shutter needs to be opened and closed while the plate is still wet.

After the exposure, the plate is rushed into a darkroom to be developed. The black-and-white image emerges directly on the metal surface in a feat of photographic alchemy.

"It's magic," said Rodriguez, with "a ton of chemistry involved."

The process is a bit unpredictable because it can be affected by dozens of variables like the air temperature. You never know precisely what you're going to get until you see the picture swimming into view under its bath of fixer chemicals. And there's no negative, so each tintype is one of a kind.

"This is like a wild card every single time," Rodriguez said. "It takes a long time to understand all the nuances."

It's also a bit risky. The collodion is highly flammable. The silver nitrate is corrosive. And ether can be hazardous when inhaled in high concentrations. Tintypes originally were called the "black arts" because handling the chemicals could leave black stains on your skin. That's what inspired the name of Rodriguez's St. Paul portrait studio: Blkk Hand (

"It's all like vaguely dangerous," said Rodriguez, who began learning the technique from photographer Zoey Melf, who currently teaches a continuing education workshop on tintype photography at MCAD.

A haunting quality

In the 21st century, tintype photography seems very gear- and labor-intensive, but it was the instant photography of the 19th century. Faster, cheaper and more portable than daguerreotype photography, which required polished silver plates and heated mercury, tintype allowed itinerant photographers to take and sell photographs on the streets and at fairs and carnivals.

Seen with modern eyes, tintype images have been described as appearing otherworldly and ethereal. The images are characterized by a shallow depth of field and an "orthochromatic" tonal range.

"It sees blues almost like white and red almost like black," Rodriguez said. "It sees a different spectrum of light, and people are really interested in seeing themselves that way."

The haunting quality may also come from association with some of the most memorable uses of tintype: documenting the carnage of the Civil War and Victorian-era memento mori photographs of the recently departed.

"There's a little bit of mystery to it," said Betty Jäger, a Minneapolis goldsmith who has hired Rodriguez to take several tintype pictures of herself, her friends and relatives. "I feel like the tintypes make a real connection to the past."

In the photos that Rodriguez has on her website, most of the individuals, couples, kids and dogs getting their portraits taken have a certain formality, a feeling that they're posing for posterity. They're rarely captured flashing a big selfie grin.

"The process is so dramatic, smiling can look cheesy," Rodriguez said.

Even celebrities tend to adopt a serious aspect when being photographed in tintype, as evidenced in a striking set of images of actors taken by photographer Victoria Will in 2014 at the Sundance Film Festival.

Instant heirlooms

Rodriguez won $20,000 in grants from the Minnesota State Arts Board to help her acquire the equipment and develop her niche in tintype.

She started Blkk Hand in 2015, shooting portraits, still lifes and even product photography on tintypes in a space in the Dow Building on W. University Avenue.

"I've made this my livelihood," she said.

She also helps others learn the technique. She's teaching a tintype workshop Oct. 26-27 at the Praxis Photo Arts Center in Minneapolis.

And she's created a mobile photo booth, hauling her 8- by 10-inch, military surplus, large-format camera, sheets of aluminum and chemicals around town so that she can shoot and develop tintypes for pop-up events at markets, street fairs, art shows and breweries.

"Literally half of my job is education," she said. "I'm educating people on what it is."

Rodriguez charges $60 to $120, depending on size, for a single tintype shot at a pop-up event. It's $200 to $400 for an hour and a half of shooting in her studio, resulting in three tintypes up to 8-by-10 inches in size.

What you get is an instant heirloom.

"I'm interested in how photography acts as an object," Rodriguez said. "There's something about holding it in your hand, the physicality of it."