Renee Fleming makes two appearances in world premieres this week. The first took place in the Boston Symphony concert on last Saturday evening, with Andris Nelsons conducting, joined by baritone Rod Gilfrey and, an unusual participant in BSO concerts, projection designer Wendell K, Harrington.

Before the new work, which ran roughly an hour and filled the entire second half of the program, Nelsons led one of the great orchestral scores from the very end of the 19^th century, Elgar’s Enigma Variations, in a generally relaxed performance that allowed the diverse orchestral colors and solo moments of each of the variations (which represented personal friends of the composers such as they might write if “they were asses enough to compose,” as Elgar explained to the music editor at his publisher’s office, A.G. Jaeger, who himself was transformed into the best-known of the variations, “Nimrod.”

The splendid current state of the Boston Symphony allows all of Elgar’s careful blends of the instruments into different shades of sonority as well as both tender reminiscence and passionate outburst, sometimes in rapid succession. Nelsons tended to take a rather long pause between each part of movements; often such pauses are entirely appropriate to allow contrasted gestures to make their effect, but perhaps some them might be more closely linkd, both to avoid the feeling of start-and-stop and to suggest a link between those variations that were closer in mood and style. Still, it is always a pleasure to hear; the delicacy of C.A.E. (depicting Elgar’s wife), the warmth of Nimrod, and the glorious assurance of  the closing E.D.U. (Elgar’s own nickname, invented by his wife and pronounced Edoo) always provide capstone moments for the piece.

Kevin Puts won the Pulitzer Prize in 2012 for his first opera, Silent Night, movingly depicting the first Christmas Eve during World War I, December 24, 1914, when opposing forces of Germany on one side, France and Scotland on the other, stopped fighting for one extraordinary night, celebrating the holiday together, and then resuming the battle at dawn—to be informed from higher command that such an event must never happen again.

Since the announcement of the Pulitzer, Kevin Puts has been in increasing demand for various kinds of music—concertos (for string quartet, flute, oboe, clarinet, percussion, marimba, violin, and cello, and he has one forthcoming written for the lively trio Time for Three, consisting of two violins and double bass.

Any composer of opera should be overjoyed to have an opportunity to write for Renee Fleming in any context. When Puts was commissioned by his alma mater, the Eastman School of Music to write a piece for the orchestra and a graduate of the school as soloists, he was most enthusiastic when Fleming was invited to be the soloist and accepted. It was only natural to choose a subject related to a significant American woman. The painter Georgia O’Keeffe was chosen, and Puts assembled a text based on her correspondence with her husband, the photographer Alfred Stiglitz. Following the first performance of this work, Letters from Georgia, at Lincoln Center late in 2016, the soprano suggested enlarging the work to include a role for Stieglitz, to give more dramatic sharp, though it was still intended to be a concert piece, without costumers, sets, or action. The expanded form bears the title The Brightness of Light.

Puts selected and assembled excerpts from their letters to one another, with permission of Yale’s Beinecke Rare Book and Manuscript Library, where they are housed. The text he created—he calls it a “libretto” with quotation marks, because there was no intention to make it an opera—traces their relationship in broad strokes from her first dry letter to him, without emotional weight, through their marriage, her move to Taos and long years living apart from him, though they stayed in touch, and finally two letters composer during the photographer’s lifetime but set by Puts as if they represent Georgia’s thoughts after his death. Some parts of these are dialogues, with lines bounced back and forth, and other are devoted to words written by one or the other alone. As an experienced opera composer, it is perfectly sensible that the “dialogues” should be set in a generally conversational style, in which the words are vital for the audience to hear, and the melodies, though present, are less coherent. For the solo passages, the “songs,” melody expands and rings and soars, in the part of both characters, though it seems to me as if Georgia’s voice and personality and individuality on the whole dominates.

The composer calls The Brightness of Light an orchestral song cycle. It is certainly not an opera, but it is also something a little more than his description suggests. In order to project the characters, who were, after all visual artists in paint and photography, Wendall K. Harrington was brought to design a series of projections that would flow throughout the performance and link the actual letters (and envelopes), along with Stieglitz’s photos and O’Keeffe’s paintings. This gives it to a slight degree the feeling of a documentary film with a soundtrack. It draws the attention affectively, especially to the paintings, sometimes in full, sometimes enlarged insets.

But as much as the images add, the real effect comes from the warm and expressive singing of Renee Fleming and Rod Gilfry, not in melodramatic operatic voices, but in a conversational tone, starting matter-of-factly and becoming pregnant with meaning. Both singers have beautiful voices, and both boast clear diction. Even in the Shed with thousands of people in it (and no walls to bounce the sound back from the sides), the narrative was mostly clear (though a performance in an enclosed space like Symphony Hall would probably be even better in that regard).

The Brightness of Light imaginatively combined a personal drama presented in orchestral music and song, as well as a very attractive introduction to a significant photographer and an important painter, in terms of their actual work—a very unusual concept for a concert, and one that was a happy success.

Steven Ledbetter, a freelance writer and lecturer on music, was program annotator for the Boston Symphony Orchestra from 1979 to 1997. He is a graduate of Pomona College and got his PhD in Musicology from New York University.