The first things to greet the audience when the curtain rises on “El último sueño de Frida y Diego” (“The Last Dream of Frida and Diego”) are a vibrant, richly hued orchestral chord and a gleaming array of candles and religious imagery. Right away, we know what’s important.

In this luminous and often irresistible opera bycomposer Gabriela Lena Frank and librettist Nilo Cruz, which had its commissioned local premiere at the San Francisco Opera on Tuesday, June 13, color — whether visual or sonorous — is the key to character.

How could it be otherwise?

In imagining a final, death-haunted reunion betweenFrida KahloandDiego Rivera, the painterly supercouple whose ambitious and distinctive achievements defined a slice of mid-20th century art, Frank and Cruz have prompted themselves to address the particulars of the visual arts in another medium.

Among the thrills of Tuesday’s opening at the War Memorial Opera House was the extent to which this new opera, which had its world premiere at the San Diego Opera in October, rises to this challenge.

On a purely visual level, “Frida y Diego” is an endless delight. Designer Jorge Ballina’s sets shift nimbly between riotously detailed crowd scenes and sparse expanses that help focus attention on the central characters. There are endless gradations of color and shape, subtly illuminated by lighting designer Victor Zapatero, and director Lorena Maza deploys the performers skillfully within those spaces.

Eloise Kazan’s splendiferous costumes, which range from the quotidian to the extravagant, deserve an entire review to themselves. A late-arriving tour de force, in which a triptych of alternate Fridas show up in some of the artist’s most distinctive guises of self-portraiture, is a crowning stroke.

Frank’s score, superbly led by debuting conductor Roberto Kalb, matches this bounty note for note and shade for shade. In her first opera, theBerkeley-born composerdraws instrumental combinations from the orchestra that are at once startlingly inventive and perfectly natural.

Her vocal and choral writing is equally arresting, full of lyrical melodies that take coherent shape and boasting a vivid rhythmic profile. Nothing in Frank’s score registers as merely a vehicle for the libretto — the music asserts its own presence at every turn.

That’s fortunate, because from a purely dramatic standpoint, “Frida y Diego” is something of a muddle. The premise, a reverse version of the myth ofOrpheus and Eurydice, offers an intriguing twist on an ancient tale. But at just over two hours, the opera never gives itself the scope to explore the ramifications.

The piece is set in 1957, on the Day of the Dead, when the spirits of those who are gone can return to Earth for just 24 hours. Kahlo (mezzo-soprano Daniela Mack, in a fiery, vocally robust performance) has been dead for three years, having finally succumbed to injuries from the streetcar accident whose aftereffects plagued her entire life.

Rivera, her much older husband (baritone Alfred Daza, sounding alternately heroic and worn) doesn’t have long to live. When we first encounter him in the Mexico City cemetery, he’s among the other mourners hoping for a visit from their lost loved ones.

•卡罗,虽然,不是cr特别感兴趣ossing over from the underworld. She’s had enough of physical pain, and the emotional buffeting she received over the course of her tempestuous marriage to Rivera isn’t anything she cares to revisit.

The one thing that could induce her to leave the underworld — and this is the opera’s fascinating invention — is the lure of painting.

“I’m coming back to my colors,” she sings just before the Act 1 curtain. “To my images, to my art.”

There’s a moment in Act 2 where she discovers why that plan isn’t workable, but if you blink you can miss it. Instead, we get a lovey-dovey reunion with Rivera, and a conclusion whose sentimentality feels like a betrayal of Kahlo’s fierce self-determination.

The two title roles were capably handled, both by artists who spent early years of their career in the training program of the San Francisco Opera. But the most dazzling contributions came in the two subsidiary roles, both from artists making memorable company debuts.

Jake Ingbar, an American countertenor with a powerful voice and insinuating stage presence, gave an exquisitely poised performance as Leonardo, a denizen of the underworld whose Greta Garbo impersonation is so well-honed he brings it above ground to bring solace to a grieving fan (even though, hilariously, Garbo isn’t dead yet — she lived until 1990).

Most unforgettable, though, was the triumphant debut of Chilean soprano Yaritza Véliz as Catrina, the underworld potentate who makes the decisions about who can and can’t get a day pass back to Earth. Singing with a mighty, richly fortified sound and dominating the stage with the imperious assurance of a petty bureaucrat (her system of physical permits is an amusing touch), Véliz was a mesmerizing presence every moment she was onstage.

The Opera Chorus, led by John Keene, gave a glorious performance as the inhabitants of Mexico City (both living and dead), filling out the smoky tints of Frank’s choral writing with pointed precision. Tenor Moisés Salazar, a gifted young Adler fellow, stood out in the course of two brief but sharply etched cameos, and Adler fellows Mikayla Sager, Nikola Printz and Gabrielle Beteag blended invitingly as the three Fridas.

“Frida y Diego” marks a series of landmarks for the San Francisco Opera in itscentennial year. It’s the first Spanish-language work to be performed here (the supertitles, appropriately, are given in both Spanish and English). It’s also the company’s first commissioned opera by a female composer, and the first opera by a woman to be presented on the main stage of the War Memorial.

To those distinctions I would add that, even with its dramatic shortcomings, “Frida y Diego” is among the most alluring and beautifully crafted operas to be commissioned by the company in a long time. May there be many more.

Reach Joshua Kosman:jkosman@sfchronicle.com; Twitter:@JoshuaKosman