The Philadelphia Orchestra spent a good part of the day Thursday in Verizon Hall doing something it hadn't done before in recent memory: reading through new scores in rehearsal with no intention of performing any of them in concert — and not knowing quite what it was going to get.

One new piece, in eternal dusk, turned the orchestra into a cloud of sound that slowly morphed. Another, called All the While, wrapped itself in Americana. Yet another, The Saqqara Bird, with novel orchestral colors and a masterly sense of structure, explored the enigma of an Egyptian artifact whose function has long stumped the experts.

There was something else exceedingly unusual about this day of score-reading: all the composers were women. The showcase is one in a number of initiatives rolled out after criticism of a 2018-19 season initially announced without a single female composer.

Kensho Watanabe, the orchestra's assistant conductor, was on the podium, playing through six pieces and then turning to the six women to ask whether balance, dynamics, and certain orchestrations and instrumental techniques, now realized by a great orchestra, were what they were expecting.

Notably, the orchestra's first rehearsal of the year also brought the first public appearance of its new president and CEO, Matías Tarnopolsky, who announced from the stage that the orchestra has decided to commission new orchestral works from these six composers. The group is starting a new mentoring program for emerging female composers. It has named Gabriela Lena Frank composer-in-residence through 2021. And in the 2019-20 season, more than half of the orchestra's programs will feature a work by a female composer.

Among the new pieces that season will be one by Valerie Coleman, known to many as the flutist of Imani Winds, who at this point is mulling for her commission taking an existing piece and putting it into orchestral form extended with new material.

The orchestra believes this is its first time commissioning an African American female composer, an orchestra spokesperson said.

Thursday's event, a collaboration with the American Composers Orchestra, was not the first time these composers have heard their works played. Still, hearing your score with an orchestra of this caliber has great value, and the day came with fringe benefits. The public was invited in, and among the hundred or so in the audience were some listeners of influence.

Among them: Nigel Boon, director of artistic planning for the National Symphony Orchestra; Peter Czornyj, vice president of artistic operations for the Dallas Symphony Orchestra (representing that orchestra's Women in Classical Music Initiative); and Cristian Măcelaru, formerly with the Philadelphia Orchestra and now music director of the Cabrillo Festival of Contemporary Music.

What they heard was diversity.

Stylistic diversity, that is. Xi Wang's Above Light, a conversation with Toru Takemitsu, in itself covered great ground, moving from worried to menacing to sensuous within minutes.

Likely Pictures in Haphazard Sky by Hilary Purrington was long on texture, starting with pizzicato strings and harp strikes that sounded like small bubbles popping.

"Could it sound a bit more cautious?" Purrington asked Watanabe about one point in the score, "maybe bring it from mezzo forte to piano?" Could the attacks at bar #97 be crisper? Should bar #188 be marked down to pianissimo?

"Wow, that was magnificent," Nina C. Young said after the orchestra played excerpts from her Agnosco Veteris. "I wish I could hear the rest of it," she said about the work, which had both a wonderful yearning and a bit of swashbuckling adventure coursing through its veins.

in eternal dusk, by Chen-Hui Jen, was striking for its use of naturalistic elements (luminous harmonics, evocative atmospherics, the use of breathy air pushed through brass instruments). In All the While, Robin Holcomb took a broad brush to American ideals of goodness, warmth, and, perhaps, the value of a national tapestry.

If part of this exercise was about exposing the scores to music critics, this critic was quite taken with Melody Eötvös' The Saqqara Bird. A dashing, energetic character sketch with a decidedly Middle Eastern flavor, it held a sustained, long-view narrative — a sense of a story unfolding in tightly linked paragraphs. It emerged as a work of great artistic clarity.

There's a paradox here, though: If the orchestra is successful in its larger initiative, there should be in a few years so many female composers in the pipeline, from girlhood aspirants to big names, that no one should have to resort to corrective measures to equal up the numbers. The ultimate goal of events such as these should be nothing less than planned obsolescence.