You can't blame Chris Potter for being a little flummoxed.

Tasked with composing a new piece of music based on one of the paintings in the Philadelphia Museum of Art's collection, the saxophonist was handed not a lush, colorful masterpiece of French impressionism or an explosion of color à la Jackson Pollock, but a stark, austere black-on-white piece by the minimalist Ellsworth Kelly.

"To be honest," Potter recalls, "my first reaction when I saw it was, 'Wow, what on Earth am I going to do with this?' "

Fortunately, Kelly provided the answer as well as the challenge. The title of his 1951 work, Seine, serves to focus the image on his canvas from a series of randomly intersecting black geometric shapes into the impression of light reflecting on water. "I ended up thinking about the flow of water, the patterns of light, and the polarities of light and dark," Potter says.

The resulting piece, composed for a new quintet featuring violinist Mark Feldman, trumpeter Ralph Alessi, bassist Scott Colley, and drummer Nasheet Waits, will be performed May 27 as part of the museum's Art After 5 series. It is one of two new works commissioned to honor Anne d'Harnoncourt, the museum's director from 1982 until her death in 2008. Seine was the first purchase made through the new Anne d'Harnoncourt Memorial Fund for Art Acquisitions.

This Friday, saxophonist Joe Lovano will premiere Shimmers of Light, his new 10-movement piece also inspired by Seine. "I've been in Paris and walked along the Seine so many times through the years," Lovano explains, "I started to think about the different seasons and times of day, and how reflections on the river change. A lot of different energy and sound and color came forth from those points of reference."

Shimmers of Light was written for Lovano's Street Band, an octet formed in the mid-'80s that features his wife, Philly native Judi Silvano, on vocals, along with woodwinds, strings, and rhythm section.

"The Street Band covers a full orchestra of sounds," Lovano says.

Both pieces and their performances were funded by a $60,000 grant from the Pew Center for Arts & Heritage through the Philadelphia Music Project. According to Sara Moyn, producer of evening programs for the museum, the commissions will "not only result in new, visionary interpretations of visual art from the collections, but will also create opportunities for musical 'conversation' between two of today's leading saxophonists, artists of separate generations, but who are equally groundbreaking in their work."

Despite a nearly 20-year age difference, Lovano and Potter are among the leading voices on the modern-jazz scene. Potter, 40, leads the electric quintet Underground and is a prodigiously inventive composer and improviser. He got his start under bebop legend Red Rodney before joining bands led by bassist Dave Holland and trumpeter Dave Douglas, and touring with the rock supergroup Steely Dan in the mid-'90s.

Lovano, 58, rose to prominence through a more traditional jazz-apprenticeship system, playing with the big bands of Woody Herman and Mel Lewis before finding his own voice. He exercises his burly tone in a surprising number of contexts, most recently via his two-drummer Us Five quintet (which features bassist Esperanza Spalding, who won this year's Grammy for best new artist), a collective quartet co-led by guitarist John Scofield, and his long-running trio with guitarist Bill Frisell and drummer Paul Motian.

Kelly, born in 1923 in Newburgh, N.Y., became influential in the minimalist, color-field, and pop-art movements in the mid-20th century. Seine dates from 1951, when he was based in Paris; he would move back to New York three years later and begin to garner greater attention. The painting was created by shading units on a rectangular grid based on randomly drawn numbers, an analogue to jazz improvisation that was not lost on either composer.

Lovano, who lives in New Windsor, N.Y., almost right next door to Kelly's Newburgh, found parallels between the artist and the composer's father, Cleveland saxophonist Tony "Big T" Lovano.

"He grew up in the same era as my dad," Lovano says, "through modern jazz and bebop, along with Charlie Parker and Thelonious Monk. He's a modern artist in our time that was on that scene. So I realized that had something to do with the way I wrote for the piece, too."

While Lovano drew on his past and his own memories of Paris, Potter responded more to the basic essence of Kelly's piece.

"Of course, I've been to Paris many times and have my own memories of walking over the bridges," Potter says, "but I didn't feel it was appropriate to approach this from a superpersonal aspect, because the painting doesn't seem very personal. It seems like it's much more about making general abstractions, so that was my approach. When it comes down to figuring out what notes to play, it's pretty organic."