As a middle-school kid in Tijuana, Mexico, Luis Fitch collected postage stamps from neighbors, steaming them off envelopes and inspecting them under a magnifying loupe.

"Through my loupe, it was a whole different world," said Fitch, an artist, designer and founder of the Minneapolis branding agency Uno. The design, the details, the layers of color. "I saw them as mini-posters."

One day, Fitch promised himself, he'd design a stamp. Now, decades later, he has.

Fitch has created the U.S. Postal Service's first stamps celebrating Día de los Muertos, or Day of the Dead — the centuries old Mexican tradition that has gained international popularity thanks partly to the 2017 Disney/Pixar movie "Coco."

The vibrant series of four Forever stamps, issued Sept. 30, depicts a family of sugar skulls surrounded by marigolds and candles. It marks a major moment for Fitch, whose Día de los Muertos work is now being embraced by brands as big as Target.

During the holiday, generally observed Nov. 1-2, the living welcome back the souls of those who have died.

"The Postal Service has never issued a Day of the Dead stamp before," said Antonio Alcalá, an art director for the USPS. "So it needed to be something that was not going to feel too challenging for people in other parts of the country who might not at all be familiar.

"It needed to feel friendly."

Alcalá first spotted Fitch's prints at the National Museum of Mexican Art in Chicago, snapping iPhone photos of them. When the USPS decided to make a Día de los Muertos stamp, Fitch's bright, graphic style came to mind.

"I didn't know what he would do," Alcalá said, "but I knew the flavor of what he might create."

At first, Fitch, 56, was convinced that Alcalá's phone call, which came on his birthday in October 2018, was a prank.

The day before, Fitch had written down the things he'd like to accomplish during the year. Among them: Design a postage stamp. He'd been inspired by a recent conference where an artist mentioned creating a stamp.

"All these memories came back to me," Fitch said.

He remembered Tijuana, where he was — by far — the youngest member of a Saturday morning stamp club. He remembered San Diego, where he grabbed a brochure at the post office and pitched a stamp that got rejected. He remembered Pasadena, where he'd designed a stamp for a class assignment at the Art Center College of Design.

That class required a set of four stamps. "Each needed to be different," Fitch said, "but all of them had to look like family."

It's a lesson that would come in handy years later.

Fitch didn't grow up celebrating Día de los Muertos in Tijuana, a cosmopolitan city so close to the United States that Halloween crept in. But early on, he became fascinated by its visuals, studying books about its iconography.

Each place he moved, he "connected with his culture," which in Columbus, Ohio, meant hanging out at the Mexican restaurant and, eventually, rebranding its visuals.

When he moved to Minneapolis in the late 1990s, Fitch created the promotional art for a Latino gallery's Día de Los Muertos festival, which became an annual practice. (This year, his sugar skulls, flowers in their eyes, advertise an Oct. 30 festival at La Doña Cerveceria, a taproom in Minneapolis.)

Fitch starts with paper cutting, a tradition known as "papel picado," scanning designs into the computer, making their edges sharper and cleaner. Over the years, he's amassed a big collection of imagery — skulls and candles, flowers and butterflies.

So when Alcalá called, he was ready: "By the end of the conversation, the stamp was finished."

Rather than create a single design, Fitch designed a set of four different but related images representing a father, mother, son and daughter.

"It helps reinforce the idea of family," Alcalá said, "which is a big part of the Day of the Dead celebration."

Even after committees settle on a subject to commemorate, a stamp can take years. So Fitch had to remain quiet.

He had to keep mum, too, about his collection with Target, released in September and already sold out in many stores. Fitch's bright, modern objects touch on all the elements of an ofrenda, a home altar built for loved ones who have died, which can include candles and calaveras, or skulls.

"I couldn't talk about the stamps, I couldn't talk about Target," he said. "For two years! To anyone! Not even my mom knew about it.

"If I told my mom, she'd tell the whole family."