Inc.'s 11th annual 30 Under 30 list features the young founders taking on some of the world's biggest challenges. Here, meet Prynt.

Prynt's device is magic in a way that's obvious only when you actually start to use it, yet the 25-year-old creators of the device have had trouble explaining it to their own families. "My father is actually one of the biggest users," says CEO Clément Perrot. "He loves the product even though he doesn't always understand everything, but at least he's printing pictures."

What Perrot and his co-founder, CTO David Zhang, have built is a smartphone attachment that allows you to instantly print the photos you take, Polaroid-style. The printing of the photos is easy enough to explain, but there's another component that Perrot and Zhang say can be hard to relay.

When you open the app on your phone and physically hover the mobile camera over a Prynt photo, it becomes an animated image within your phone's screen. Groups may merge into formation for a portrait, friends will sing "Happy Birthday." Visually, it's the closest thing you'll experience next to the moving images of the Muggle world of Harry Potter. It's perfect for rarely still babies. Lovers often use the photos to code messages to each other, while some may use the medium to record magic tricks. 

Perrot and Zhang came up with the idea for Prynt during a semester at the Center for Entrepreneurship and Technology at University of California, Berkeley, in the fall of 2013, before completing their master's degrees in engineering at École Polytechnique in Paris. While attending the same party, they noticed a group of folks excitedly crowding around a person with a Polaroid, and decided to create a device that allows people to print photos directly from their phones. A year later, a stint at accelerator Hax in Shenzhen inspired development of the "moving picture" aspect.

Last year, the co-founders launched a Kickstarter campaign and raised more than $1.5 million in funding. (They also raised a seed round of $2.3 million, and a convertible note of $1.5 million.) Prynt has shipped roughly 20,000 cases since it hit the market in December, with sales limited by inventory--and not demand--according to Perrot.

Prynt's staff, previously split between San Francisco and Paris, is as of October entirely based in San Francisco, with 25 employees working in an airy warehouse in the city's Dogpatch neighborhood. Perrot says they plan to hire more employees in the near future. 

The MoMa and the Andy Warhol Museum have inquired about selling the product in their museum shops, according to Perrot. The pair are working on expanding the footprint of the product in Asia, where they expect the intersection of the ubiquity of photography and emphasis on gifting to drive Prynt to massive popularity.

There's obviously traction, but challenges also remain.

It's only natural that someone who works in tech, or who has a job involving new-ish technologies or platforms, has the experience at some point of not being able to explain what they're working on to their parents or grandparents. Perrot and Zhang are not unique in that respect. One challenge is concisely explaining Prynt's different components to someone who grew up with Polaroids and not with smartphones.

Perrot says his 50-year-old father, a crop farmer in the Paris-area town of Ablis, understands the moving picture aspect of the app--he just has trouble working with app features such as privacy settings and properly charging the device. Zhang's parents are likewise new to using the app despite his engineer father's having helped him troubleshoot issues with earlier iterations of the product. He says his parents, in the Paris suburb Guyancourt, only recently purchased their first smartphones.

The thing with Prynt is that it's a camera, a product that appeals to anyone, really--friends, family, parents, grandparents. Perrot and Zhang themselves have no professional photography experience--they just enjoy taking photos as much as anyone else does. Ideally, it's accessible to anyone regardless of skill levels in photography or technology.

The next challenge for Perrot and Zhang is trying not to bulldoze through the tentative meeting of physical and virtual where the spark behind Prynt lies. The quandary: As Prynt develops, how does the startup navigate its relationship with social media?

Already Prynt is somewhat integrated with social media. The app can read photos taken using the Prynt case when they are posted online. Snippets of video taken with GoPro cameras and Vine videos can also be pulled and printed as photos from the Prynt camera and their still, physical versions read with the app to play the video.

But the nature of social media is in conflict with the aim of Prynt. Posts on sites like Facebook and Instagram stack up so quickly that each picture is effectively ephemeral, says Zhang. "You see it once and then it disappears after one day or even after a few hours." Printed photos, by contrast, are meant to last; plus, they're more intimate than posting for all to see," he notes. "It's kind of like a really special gift."

The two hope to retain a sense of intimacy in the product even as usage grows and opportunities to make the app and product more social arise.  "Every picture is like a door between two people," says Perrot.