Denim apparel is making a comeback in shops and fashion magazines. But some of the new designs-from denim leggings for women and jean shorts for men to head-to-toe denim outfits for both sexes-risk pushing the revived trend too far.Jessica Biel graces the cover of the February issue of Vogue wearing a denim jacket by Ralph Lauren Collection over a RRL Ralph Lauren denim vest. A current two-page print ad from Dolce & Gabbana’s D&G line features models in a club setting wearing head-to-toe denim and denim dresses while a denim handbag rests on a table.

..All that denim is starting to reach the public, making its way into department stores like Macy’s and Saks Fifth Avenue, as well as J. Crew and Banana Republic, which recently introduced a denim collection that includes trench coats and shirt dresses.

Part of the renewed interest in denim may have to do with the economy: hard-times chic in hard times. A return to gritty, more down-to-earth wear; a rebellion against flashy silk dresses and banker suits.

Simon Kneen, creative director and executive vice president of design at Gap Inc.’s Banana Republic, whose current ads feature models wearing head-to-toe denim, says he was inspired in part by the indigos in Jasper Johns’s paintings and, amid the economic downturn, “the wonderful optimistic feeling of blue skies and springtime and feeling really positive and optimistic.”

The attention on denim may also represent designers’ and retailers’ inability in the past year to come up with styles or must-have items that consumers can get excited about. “Denim is a relatively safe choice because it always sells,” says fashion-trend expert David Wolfe.

But denim-on-denim? Such designs can border on camp or tacky, in the wrong hands.

In recent years, denim-on-denim ensembles have been derisively referred to as “The Canadian tuxedo” after a denim-clad character named Denim Dan gets ribbed for his look in the 2001 movie “Super Troopers.” Britney Spears and Justin Timberlake were pilloried when they showed up in a denim dress and a denim suit to the 2001 American Music Awards.

Mr. Kneen of Banana Republic says denim on denim looks fresh because it hasn’t been around for some time. “Maybe it’s been a fashion no no but it’s a fashion OK at the moment.”

Some consumers are wary. “That’s something that doesn’t appeal to me aesthetically,” says Natalie Pon, a 21-year-old medical student in Dallas. While she’s a fan of denim leggings and will consider buying denim shirts, “I think it will be hard even for me to wear denim on denim and come off looking good,” she says.

Some retailers are cognizant that some designs may be too much for customers.

“We’re not recommending denim on denim,” says Colleen Sherin, women’s fashion director at Saks Fifth Avenue, a unit of Saks Inc. “In reality, women will want to mix and match their denim pieces and not wear their denim head to toe.” Instead, Saks will display mannequins and models wearing, say, a denim jacket over a floral dress in its stores and advertising.

For men, there are denim shorts by Gilded Age. Though Saks’ men’s fashion director Eric Jennings says these shorts are more contemporary, they still may not pass muster with some who don’t think men should ever wear jean shorts.

In their forthcoming book “Undateable,” which lists 311 things men do that “guarantee they won’t be dating or having sex,” authors Ellen Rakieten and Anne Coyle rank jean shorts as the number one don’t. Wearing denim on denim ranks 18 on their list.

Eric Brewer, a video producer in Washington, D.C., recently wore a dark denim jacket with a slightly lighter faded pair of jeans, paired with a black shirt, and plaid scarf to a party. Still, even he wouldn’t go the next step, putting on a denim shirt with a denim jacket and jeans. “It can look silly, too contrived,” he says.

This article was written by Ray A. Smith for the Wall Street Journal.