Britney Spears, Kelly Clarkson and More Go Under the (Digital) Knife

April 14, 2010 — -- Britney Spears is paying her dues, giving fans a glimpse of what her body really looks like.

The 29-year-old pop star has allowed the pre-airbrushed images from a fashion shoot she did for Candie's to be shown adjacent to the digitally-altered ones, so people can see how a little Photoshopping can have a huge impact on how stars look.

Spears' waist, bottom and thighs look noticably slimmer in the retouched photos. Her airbrushed skin bears no bruises or cellulite, and a tattoo has even been erased from her back.

Jessica Simpson recently graced the cover of Marie Claire sans makeup and digital touch-ups to illustrate the similar point that celebrities don't always look like they do in photos.

But not all acts of airbrushing are so honest -- it's rare that the "before" image stands alone or gets released to the public at all.

"The more and more we use this editing, the higher and higher the bar goes. They're creating things that are physically impossible," said Hany Farid, a Dartmouth College professor of computer science who specializes in digital forensics and photo manipulation. "We're seeing really radical digital plastic surgery. It's moving towards the Barbie doll model of what a woman should look like -- big breasts, tiny waist, ridiculously long legs, elongated neck."

Below, four more recent instances of seemingly extreme airbrushing.

Kelly Clarkson

Kelly Clarkson has battled weight ups and downs for years, but on the cover of September's SELF magazine, she looked slimmer than ever.

She was photoshopped, and the magazine wasn't afraid to admit it.

"Yes, of course we do post-production corrections on our images," SELF editor in chief Lucy Danziger told "Entertainment Tonight." "Kelly Clarkson exudes confidence, and is a great role model for women of all sizes and stages of their life. She works out and is strong and healthy, and our picture shows her confidence and beauty. She literally glows from within. That is the feeling we'd all want to have. We love this cover and we love Kelly Clarkson."

In the past, the "American Idol" winner has raved about the photoshop jobs done on her album covers. She still seems comfortable in her own skin, digitally retouched and in real life.

"My happy weight changes," Clarkson says in the September issue of SELF. "Sometimes I eat more; sometimes I play more. I'll be different sizes all the time. When people talk about my weight, I'm like, 'You seem to have a problem with it; I don't. I'm fine!' I've never felt uncomfortable on the red carpet or anything."

Kate Winslet

Many Hollywood actresses wax poetic about the importance of a healthy figure; Kate Winslet is one of the few that actually walks the walk. In 2003, she criticized British GQ for whittling her figure on the magazine's January cover, telling Britain's GMTV, "I don't want people to think I was a hypocrite and had suddenly gone and lost 30 pounds, which is something I would never do, and more importantly don't want to look like that. ... They made my legs look quite a bit thinner. They also made me look about 6 feet tall, which I'm not, I'm 5 foot, 6 inches."

Given that, it's surprising another magazine would apparently commit a similar sin. But Winslet graced the December 2008 cover of Vanity Fair looking svelte beyond belief. A photo spread inside the issue features Winslet sprawled atop a fur throw, the small of her back carved out as if it was made of clay.

Winslet opened up about this cover too, but this time it was to deny her image had been manipulated.

"Kate is furious at suggestions that her body has been airbrushed," her publicist told People magazine in November."She is in terrific shape and what you see is how she looks or she would never have agreed to pose for those shots."

Dartmouth professor Farid isn't buying it.

"All the body fat is removed, all the wrinkles are removed, the skin is smoothed out," he said. "Some of that is makeup and lighting -- professional stylists can do wonders -- but almost certainly what's been done is all of her blemishes and wrinkles have been digitally altered. There's a Photoshop tool that creates a very smooth effect. Effectively what you do is paint over the whole body."

Kate Moss

Kate Moss, paparazzi victim, doesn't seem to be related to Kate Moss, Vogue cover girl. The supermodel took on a new skin tone for the British edition's December 2008 cover, apparently thanks to the work of retouchers. But Farid characterized the images as two extremes, neither one an accurate depiction of Moss. (British Vogue did not immediately respond to requests for comment.)

"She probably looks like something between those two," he said. "In the studio you have very soft lighting, very good cameras, you're waiting for the right pose. The paparazzi are horribly unfair. They're shooting with flash, the images are grainy. It's a worst case versus a best case, unrealistic scenario."

Heidi Klum

You'd think Photoshop couldn't touch one of the world's premiere supermodels. You'd be wrong. Even with Heidi Klum's goddess- like proportions, Italian GQ still apparently felt the need to rebuild the "Project Runway" host's physique for its December 2008 cover and photo spread.

"Her torso was probably elongated, they almost certainly trimmed everything out," Farid said. "And if you talk to the people who do this, they do the same thing to every model. It's a cookie-cutter thing." (Italian GQ did not immediately respond to requests for comment.)

No one wants to reverse the course of technology. But when it comes to digital photo manipulation, less really may be more.

"I think it would be interesting for fashion magazines to return to some level of sanity, to say 'here are the things that we're going to do to the images,'" Farid said. "Be up front about it. I have no problem with removing blemishes, taking away a stray hair, playing with the lighting -- it's creating a neck that's three inches longer than any human is capable of having."

"There is a bigger picture here beyond the fashion magazines," he added. "It's our ability to trust photographs. When fashion magazines create such magnificent pieces of art, it really starts to chip away at our ability to trust what we're looking at. It's why people are so skeptical of what they see."