WASHINGTON — They posed grinning beside a bust of George Washington and stood solemnly in front of a portrait of John F Kennedy. A few even caught President Barack Obama as he walked across the South Lawn to Marine One.

For visitors to the White House, yesterday (July 1) proved cause for rejoicing — and a post or two on Instagram — as Mrs Michelle Obama announced the end of a 40-year-old ban on photography during public tours. The first lady revealed the news in a video posted early yesterday in which she literally tore up a sign bearing the rule.

The move, which drew near universal praise, is likely to generate a stream of positive images for the White House and the first family, especially among young people using social media.

Dr Robert Dallek, a presidential historian, said the change would bring greater transparency and openness to the White House, particularly at a time when Republican presidential candidates looking to position themselves as Washington outsiders have criticised the administration for being out of touch.

“They don’t do these things without political considerations,” Dr Dallek said. “I guess they want to show that they are not hidebound. They’re not strapped down by traditions that limit what goes on.”

The photography ban was originally put in place to address a range of concerns, including the damaging effect of flash photography on artwork and delays in tours as visitors stopped to snap shots and strayed from the tour route.

Advances in camera technology, though, now allow high-quality photos to be taken without a flash.

The White House’s decision was also an acknowledgement of the near impossibility of stopping all visitors from using cellphones to record and widely share personal experiences. Institutions that still ban photographic equipment, like federal courts, often demand that visitors surrender their cellphones, an increasingly burdensome requirement.

Many tourists who arrived at the White House yesterday had not heard about the change in the rules. They found new signs reading “Photography is encouraged” and “Use the hashtag #WhiteHouseTour to share your experience”.

While cellphone cameras and still-photo cameras with fixed lenses no longer than 3 inches are now allowed, video cameras, tablets, tripods and camera sticks are still prohibited. Flash photography and live-streaming are also banned.

As for security, the Secret Service declined to comment on the changes, but the move suggested that the agency saw no imminent risk. Visitors to the White House may have noticed another change, too: Sharp spikes that were being installed on the fence outside.

Around the East Wing, lines formed as visitors waited to pose next to artifacts or paintings. But most people did not seem to mind the added wait, even as some families snapped shot after shot.

In the State Dining Room, Ms Kim Kesler watched her daughter Chloe photograph a portrait of Abraham Lincoln.

“She is taking a lot of pictures,” said Ms Kesler, of Los Angeles. “She won’t let go of the camera. This is awesome.”

Nearby, Mr Korey Richardson, 47, of San Jose, California, was enthusiastic about the photo opportunities.

“This is my first time here,” he said. “I’m taking tons of pictures, at least 30 so far. I’ve already uploaded some to Facebook friends.”

Mrs Michelle Obama’s video greeted each group as they entered the East Wing. Those arriving early even had a chance themselves to tear up copies of the old sign prohibiting photography.

“Let me get a shot of that,” said Ms May-May Horcasitas, originally of Hong Kong and now living in Miami Beach, Florida, as she watched the video.

After taking a still photograph, she turned to the Obamas’ two dogs, Bo and Sunny, who were sitting nearby to greet visitors.

In the video, Mrs Michelle Obama says, “If you’ve been on a White House tour, you may have seen this sign: ‘No photos or social media allowed. Your cooperation is appreciated’.”

“Well, not anymore,” she says, before ripping the sign in two.

Then, in a nod to the casual nature of social media and the convention of funny outtakes in movies, the video provides an outtake of her laughing and pretending to rip a sign.

Outside the White House on 15th Street North-west, many visitors lining up in the July heat said they were already planning their shots.

“My Facebook is going to look awfully good today,” said Ms Kim Gregory, 59, who was holding an iPhone in a gold case.

Ms Gregory, of Ventura, California, who was visiting the White House for the first time, said she felt as if she were back in the fifth grade.

“I’m having a better week than Obama,” she said, “because I have a phone and a finger to use my phone, and I’m at the White House.”

The rule change came just before the July Fourth weekend and the height of the tourist season. Families filing out of the White House grounds said the lifting of the ban had greatly improved their experience inside the landmark.

“I think it kind of does change things,” said Mr Craig Cook, 45, of Sacramento, California, who stood with his wife Libby, and his two daughters in Lafayette Square, which faces the White House. “We prepared the kids. We said, ‘You’ve got to treat your eyes like cameras.’ But this will make these memories last longer this way, without the fuzzy filter of memory.”

Ms Julie Keffer was already posting photos on Facebook as she, her husband and her son crossed the street after leaving the White House. She paused with a reporter to swipe through a couple of dozen shots on her iPhone.

The family, visiting from Oyster Bay, on Long Island, had posed together for a photo with a portrait of Theodore Roosevelt, a former resident of their hamlet. But Ms Keffer said she and her husband had split up to get solo shots with Kennedy and Reagan.

“It’s awesome,” Ms Keffer, 44, said of the rule change. “You’re going to see Christmas cards with everyone’s pictures at the White House this year.” THE NEW YORK TIMES