Beauty is an elusive but essential idea. We think we know it when we see it or feel it. And while parsing beauty might seem to be the job description of the art critic, most people — curators included — feel way more comfortable talking about something else.

“Posing Beauty in African American Culture” at the Delaware Art Museum through Jan. 29 is, consequently, a show-not-tell exhibition. It does not tell us what beauty is or what we ought to think about it. If you finish looking at the 104 works in the show (nearly all of them photographs) and have an enriched idea of beauty, it is because of what you saw in the images, not because of any writing on the wall.

The exhibition, which has been crisscrossing the country for about a decade, stands as a sort of companion to the “30 Americans” show currently at the Barnes Foundation (through Jan. 12), and some of the same artists are included. Both are large group shows that have helped to establish an A-list of African American artists in the early 21st century. But while “30 Americans” is intended to showcase a private collection, “Posing Beauty” is the outgrowth of a curator’s obsessions.

Deborah Willis, who organized the show, is a photographer and professor at New York University. She began collecting this material over many years of working on other projects. The first result was an extraordinary book, with the same title as the show, which was published in 2009. This brought together nearly a century and a half of images, by both black and white photographers, of how Americans of African descent have presented themselves through costume, cosmetics, and attitude.

While the show includes the work of many distinguished artists, the focus is on the people in the pictures—how they look and how they seem to feel about how they look.

There are celebrities, such as Michelle Obama, Joe Lewis, and a youngish Michael Jackson looking heartbreakingly normal. In Ernest Withers’ photo, the music star and record executive Isaac Hayes wears a boldly striped lounging jacket that echoes the striped wallpaper in the room, and a sculpture of two hands holding a shiny ball draws the eye back to Hayes’ shaved pate. The shaved head was a new look in the 1970s, and Hayes presented himself as a shaper of the culture.

There are also bathing beauties galore, including a group by John Mosley on the beach at Atlantic City and a huge grid, titled Posing Beauty, by Hank Willis Thomas, that shows every young woman who posed in a bathing suit for the magazine Jet over a period of several years. Many of them had clearly straightened their hair, using the products of some of the magazine’s chief advertisers. One can’t help thinking that many of them would have looked more beautiful if they had done less to themselves. We are not living by their standards of beauty, though, which were shaped by racism, technology, and current fashion.

Most of the people in the show are not celebrities or even aspiring models, but rather ordinary people trying to look their best. Thomas Askew’s photograph of an Atlanta-based music ensemble, taken around 1900, documents a striving for respectability. The same goes for his photo of a young woman taking piano lessons from an elegantly suited male teacher with starched cuffs and collar. They reflect an assumption that black people needed to look much better than white people in order to be seen at all.

Willis herself traces the origins of the book and show to her upbringing in North Philadelphia. Her mother, Ruth Ellen Holman Willis, ran a beauty parlor out of their house. It brought together ministers’ wives, domestic workers, entertainers, and many others who had regular appointments and enjoyed telling stories to the beautician’s daughter. Willis’ father, Thomas, was a tailor with his own shop in West Philadelphia, who made clothes for both men and women.

While Willis certainly wants us to think about beauty in a philosophical context, she grew up in beauty as a business. Being beautiful might be a natural gift or even a moral state, but trying to be beautiful requires effort and attention, along with imagination. It often also requires mirrors, since beauty is often about self-consciousness.

Perhaps the key work in the show is Carrie Mae Weems’s mirror-image self-portrait, “I looked and looked to see what so terrified you” (2006). The artist, looking extremely well-dressed in a formal dress made with folkish quilting, holds a hand mirror into which she stares. The photograph shows a formidable person with a normal twinge of anxiety about how she looks. She is only terrifying if you make her so. It is entirely in the eye of the beholder.

Many of the show’s most striking images are self-portraits. Omar Victor Diop photographs himself as famous historical figures, such as Frederick Douglass, in a style that recalls the painter Kehinde Wiley. Renee Cox, dressed as a superhero in thigh-high patent leather boots, seems to lounge on the crown of the statue of liberty. And in a video, Kalup Linzy performs in beard and evening gown as a soul diva for our ambiguous time.

All are, as the show’s title suggests, striking a pose. All are aware that photography is not a window to truth but an occasion for artifice. And they try to make themselves into something memorable.

A century ago, W.E.B. DuBois complained that white photographers did not even bother learning to set their lights to properly illuminate dark skin. Today, in the age of Beyoncé, with Meghan Markle in the English royal family, it seems that many of our icons of fashion and style have African ancestors. Some would ask whether such a race-conscious exhibition remains relevant.

The best way to look at the show, I’d say, is not as a critique or a complaint, but as a celebration. Looking good is hard work. It can be an act of courage. “Posing Beauty” invites us to look more carefully than we might have to see some people who look amazing.

ON EXHIBIT

Posing Beauty in African American Culture

Through Jan. 29 at Delaware Art Museum, Wilmington.

Hours: 10 a.m.-4 p.m. Weds.-Sun., with evening hours until 8 p.m. on Thurs.

Admission: Adults, $12; seniors, $10; students and children ages 7-18, $6 (kids under 7 free). Free to all Sundays and from 4-8 p.m. Thursdays.

Information: 302-571-9590, delart.org.