Executive Director Malcolm Warner, left, and Janet Blake, curator of early California art, watch as the Ferdinand Deppe's "San Gabriel Mission" is hung at the Laguna Beach Museum of Art. (Don Leach, Coastline Pilot / October 30, 2012)

Ferdinand Deppe's painting of the San Gabriel Mission underwent a long journey before landing in the Laguna Art Museum's permanent collection. But it didn't always travel first-class.

In fact, when collector Nancy Moure first encountered the painting two decades ago at a gallery in Pasadena, the dealer told her that the painting had recently been found in a drawer. And not to protect it from sunlight or dust — the painting was serving as the liner of the drawer.

Moure, though, saw a unique value in the piece and gladly shelled out for it. Thanks to her efforts, Deppe's landscape, which curator Janet Blake believes to be the oldest oil painting completed in California, has a home in the vault at 307 Cliff Drive.

This weekend, the painting, titled "San Gabriel Mission" and painted circa 1832, will hang alongside other works in the museum's permanent collection. The exhibit, which opens Sunday and runs through Jan. 20, features California works from the 19th century through the present.

Amid the many famous names on the artist roster — among them Richard Diebenkorn, Ed Ruscha, William Wendt and Clarence Hinkle — Deppe may sound relatively obscure, but his work serves as a historical keynote of sorts for the exhibit. So just how renowned an artist was he, and how good is his painting?

According to Moure and Blake, the answer to both questions is: not very.

"It certainly speaks to it being a kind of self-taught artist," Blake said. "On the other hand, I think it's quite remarkable in its description. I find the composition very interesting. You have the Gabrieleno Indians there in the front right corner, so I think, compositionally, it's very nice."

Moure, for her part, called it "a primitive painting." But given Deppe's circumstances, that lack of finesse was understandable.

According to a booklet that accompanied the museum's 2009 "Collecting California" exhibit, Deppe was a German explorer who collected natural history specimens from Mexico and later worked as an agent for a hide trader. In between his business endeavors, he traveled through the land that later became California and sketched and painted images of the burgeoning settlements.

"He was like a traveling salesman," Moure said.

The painting, which measures 27 by 37 inches, depicts the exterior of the mission on a cloudy day, with a mountain range in the background and missionaries and natives carrying out chores in front. With the mission relatively far back, the foreground focuses on a hut where a settler converses with a Gabrieleno man by the entrance.

Blake, who curates early California art for the museum, is not sure if any of Deppe's other paintings survive. For that matter, she can't say for sure that "San Gabriel Mission" is California's oldest oil piece, although she hasn't heard of any earlier ones. Jean Stern, executive director of the Irvine Museum, also believes Deppe's work is the state's first painting on record, but art historians at USC and UC Irvine could not substantiate the claim.

Regardless of whether Deppe's work is a historical milestone, it fills a gap for the museum's collection. According to Blake, the next earliest painting the museum owns is from the 1860s, leaving "San Gabriel Mission" as the only artifact from the decades prior.

Since Moure donated the painting to the museum in 1994, it has appeared several times in exhibits and been reprinted in books for both adults and children, Blake said. Last year, the museum lent it to La Plaza de Cultura Y Artes in Los Angeles for six months.

At the Laguna Art Museum this fall, Deppe's work will hang in the main galleries. In addition to longtime parts of the permanent collection, the show will also feature a new acquisition: George Herms' "Pound Box — A Tableau," a mixed-media assemblage dedicated to the poet Ezra Pound.

Two other fall exhibits, both scheduled to run through Jan. 20, will also open Sunday. A self-titled watercolor show by Timothy J. Clark is on display in the upstairs gallery, while "Ex·pose: Macha Suzuki," featuring installations by the Los Angeles artist, shows in the downstairs galleries.

michael.miller@latimes.com

Twitter: @MichaelMillerHB

If You Go

What: "The Permanent Collection"

Where: Laguna Art Museum, 307 Cliff Drive

When: 11 a.m. to 5 p.m. Fridays through Tuesdays, 11 a.m. to 9 p.m. Thursdays from Nov. 4 through Jan. 20 (closed Wednesdays and holidays)

Cost: $7 general admission; $5 students, seniors and active military; $3 per person for groups of 10 or more (reservations required); free for children under 12 and museum members

Information: (949) 494-8971 or http://www.lagunaartmuseum.org