For decades, muralist Judith Francisca Baca has painted the untold stories and overlooked histories of the city’s ethnic minorities on buildings, outdoor walls and in public places all over Los Angeles. A visual artist with an international reputation, she has literally altered the face of L.A., especially in communities that can now look up to see their own heroes and achievements heralded in bold, colorful images.

Committed to the creation of art that honors what she terms “public memory,” Baca utilizes the mural-making process to span a racial and cultural divide and spark a dialogue among diverse groups focused on whose story public art should tell.

As a 27-year-old community-outreach worker, she first tapped into this coalescing power of art in 1973 when she discovered that rival gang members were willing to call a truce to help her create a mural in a city park. Later, as founder of the first City of Los Angeles mural program, Baca saw more than 400 murals produced citywide by 2,000-plus participants over a decade.

Since then, she has engaged thousands — young and old, scholars and juvenile offenders, residents of the barrios and affluent enclaves alike — in the planning, design and creation of public murals. She recently recounted her own family history in a new, 10-foot-by-50-foot mural, “La Memoria de Nuestra Tierra” (Our Land has Memory), unveiled at the Denver International Airport.

Baca’s “Great Wall of Los Angeles”, completed in 1984 along the Tujunga Wash flood-control channel in Studio City, still stands as a golden example of this collaborative process: The half-mile-long mural, the longest in the world, celebrates the contributions of ethnic minorities to the history of California and America. The work, which she calls a monument to interracial harmony, took Baca and 700 residents — hundreds of them young people from all over the city — 12 years to complete. Supporters of the wall are currently trying to help the artist raise $1 million to finish the mural’s historical timeline and another $500,000 to restore the weather- and time-ravaged scenes.

“An average mural panel, measuring 350 feet long, took 80 people nine weeks to paint,” Baca recounted.

Today, Baca heads up a much different enterprise at the helm of the UCLA César Chávez Digital Mural Lab at the Social and Public Art Resource Center (SPARC).

In a former garage where police squad cars were once repaired, students participate in a groundbreaking workshop/class called “Beyond the Mexican Mural — Muralism and Community Development,” creating art with and for Angelenos. But instead of paints and airbrushes, students — many of whom have never picked up a drawing pad before — use high-speed computers, scanners, electronic tablets, digital cameras and software programs to create large-scale images that blend together real and virtual art.

“We no longer need hundreds of people to hold up paper against the wind,” Baca said in the art studio/lab where she and her students experiment with different materials on which these large, complex images can be printed before being installed.

“We are working on the cutting edge of this field, utilizing absolutely new approaches to muralism,” said Baca, a professor in the César Chávez Center for Interdisciplinary Instruction in Chicana and Chicano Studies and also soon to be on faculty in the Department of World Arts and Cultures.

SPARC, a nonprofit community-education and arts organization, was cofounded by Baca in 1976 before she became one of the few tenured Chicana professors of visual arts in the nine-campus University of California system. Through SPARC, students create digital murals using Baca’s approach of delving deeply into a project through intensive historical research before generating a single image.

“I learned that art is not about the final result; it’s the process that counts,” said UCLA senior Jennifer Araujo. “Rather than just making art and imposing it on the community, it’s about including the community in what is to be created.”

One primary example of this process is “Witnesses to the History of Los Angeles,” six murals that tell the personal histories of people of color — a struggling Filipino farmworker; a former slave who became a beloved community worker; a “cholo” in sunglasses. Created by students for the California Plaza amphitheater and a theater production staged there, the murals, mounted on translucent vinyl, now travel according to need.

“They’ve been taken on a protest march for affirmative action at UCLA,” said Baca, smiling. “They’ve also ‘witnessed’ a Jesse Jackson rally and a hunger strike. They’ve even been on the Internet.”

Six other student murals now hang in the community center of Estrada Courts, one of the oldest housing projects in East Los Angeles. In 1996, Baca and 15 students accepted an invitation from the residents to create the artworks for the common area.

“The students literally adopted these families. They ate Sunday dinners with them. They listened to their stories,” said Baca.

The images that emerged from Estrada Courts are poignant symbols of peoples’ lives: A photo of a young girl, seen through a bullet-shattered window, dominates one work; while studying at home, she had been shot in the foot by a stray bullet. Around her are arrayed images of smiling families and children at play, symbolizing hope for a more peaceful future.

The latest student work ties directly into the rich history of mural-making in Los Angeles, specifically a piece by the late Mexican muralist David Alfaro Siqueiros, “América Tropical.” In 1932, Siqueiros, whose work is considered on a par with that of Diego Rivera and José Clemente Orozco, was commissioned to memorialize tropical America on an Olvera Street building.

Civic leaders envisioned a scene that tourists might enjoy — of lush jungle beauty, Mayan temples and happy natives. While those elements emerged as the work progressed, the finished mural — completed by Siqueiros the night before its unveiling — offered a much harsher interpretation: a crucified Mexican Indian with a vulture-like American eagle perched above. Siqueiros, a revolutionary and a Communist Party organizer, would say later that he never intended to portray “a continent of happy men, surrounded by palms and parrots, where the fruit voluntarily detached itself to fall into the mouths of the happy mortals.” “América Tropical” was almost immediately ordered whitewashed.

As his only surviving public mural, “América Tropical” remains hidden behind a protective curtain and fiberglass cover. But it is on the verge of a resurrection being engineered by the El Pueblo de Los Angeles Historic Monument and the Getty Conservation Institute. Conservators have removed the whitewash, cleaned and stabilized the mural, and a campaign is being launched to raise $3.7 million to build a shelter, interpretive center and viewing platform from which the public can see this once-censored work.

As visitors make their way to the Siqueiros mural center, they will pass a contemporary mural that places Siqueiros in the context of the social tumult of his time. Using 3-D software to “explode” an image of “América Tropical,” Baca and her students show the muralist through the jagged outline of his crucified peasant, suspended in space over the Los Angeles River. The far-off landscape below shows fragments of historic scenes of desolation and poverty: breadlines, sweatshops, forced deportations, the Dust Bowl migration.

“When people see this piece, they will understand what was happening at the time he painted it — a vision of Los Angeles at the turn of the century,” said Ramón De La Rosa, a UCLA graduate who worked on the project. Two more student works, including “The Corn Goddess,” will eventually be installed in the entrance way.

“Being in this class was the most unique learning experience I have ever had,” said De La Rosa. “What we learned went beyond art; we learned to work together creatively. I’ve never had an experience like that, and I don’t think I ever will again.”

Baca is determined that her students’ work be more than just the creation of art.

“They must research widely, but they also must have dreams and visions of their own and not just spout back rote information,” she said. “They are creating sites of public memory. They must ask themselves, ‘What should we remember? Whose story should we tell, and why?’’