A Portland advertising agency received national attention Friday for creating an L.L. Bean print advertisement that is visible only in sunlight.

The ad, which ran as an insert in Friday’s New York Times, came about through a combination of strategy, technology and creativity, according to Leeann Leahy, CEO of The Via Agency.

Indoors, the ad appears to be mostly blank space. It contains just a few words scattered across the page, which say, “L.L. Bean,” “Be an outsider,” “Bring this outside,” and “No, seriously. Take this outside.”

When exposed to sunlight, the ad’s missing text appears in sky blue ink in a manner similar to a Polaroid photo developing, but faster. It begins, “Welcome to the outside. Where there are no strangers. Only friends we haven’t met yet.”

The ad goes on to extol the virtues of an outdoor life, and it encourages readers to explore the outdoors. It does not specifically mention L.L. Bean or its products. Once the ad is taken back indoors, the text quickly disappears.

Leahy described the text as a “manifesto” that was developed by the agency as a guide to the ad campaign it is producing for L.L. Bean, which is called “Be an Outsider.” She said it originally was intended for internal use only.

“We wrote it so that everyone understood what ‘being an outsider’ meant,” she said. Because of client confidentiality concerns, she declined to reveal the cost of the ad.

Via began working with the Freeport-based outdoor retailer in March after competing with other agencies from around the country for the L.L. Bean contract. The first Via-produced ads for L.L. Bean began running in July.

Early on, one of the agency’s creative teams came up with the idea of using photochromic ink, which changes color under ultraviolet light such as that of the sun or a blacklight, to prompt readers to actually take the ad outdoors in order to read it, Leahy said. It was decided that the manifesto would be ideal for such an ad.

“The guys at L.L. Bean really loved it,” she said. “The challenge was, ‘Can we print that?’”

Via contracted with a company called Chromatic Technologies Inc. in Colorado to produce the inserts, which were not actually printed on New York Times newsprint. The company, also known as CTI, has used specialty inks to produce a broad range of color-changing marketing materials and packaging for products such as Coca-Cola soft drinks, Duracell batteries, Lay’s potato chips and Coors Light beer.

The light-sensitive ad received widespread praise on social media Friday, and an online feature about it by the trade publication Adweek was the site’s most popular story of the day.

“We’re very excited about the response we received today,” said Chris McDonough, chief marketing officer at L.L. Bean. “We really wanted to kickstart the campaign with something that would be pretty unique.”

McDonough said the New York Times ad was the product of “a lot of conversations around how you could get people to take a blank piece of paper … and take it outside.”

The “call to action” aspect of the ad really appealed to L.L. Bean executives, he said. It got people to get up and go outdoors, which is the whole point of the ad campaign.

The sunlight-sensitive ad was meant as a one-off but could be repeated in some form in the future, McDonough said. Leahy said her agency has other inventive ideas for L.L. Bean ads that it intends to deploy in the future.

“Of course we do … but I can’t tell you what they are,” she said.