The idea came to him during a visit to Tokyo, in 2006. "When I first got high up, the scale of the city was awe-inspiring," James recalls.
"To be in it, it's bustling and chaotic, but when you come out of those lifts, you don't have that frantic feeling of thousands of images all around you. You just have this metropolis.
"I knew I liked the feeling of looking out of the window of that city. But if I just took a photo of the city, it wouldn't be that interesting."
Trial and error
With that in mind, James began experimenting with his camera, a Mamiya RB67, which could switch between taking Polaroids and film.
The Polaroids allowed him to experiment with different exposures until he found the right combination of a person's silhouette and the city.
"Each little variant could change the image quite drastically," James explains. "The Polaroid was like a sketchbook. Once I got the basics, I would switch to film and shoot a whole roll."
Soon after, James moved to China on assignment with Getty Images, in a move inspired by his developing interest in the country.
The country would yield some of the series' most powerful images.
In one photo, taken in Shenzhen, China, a child waving a flag seems to encapsulate various ideas of the country's rapid urbanization -- both its ambition and pride, but also the tremendous sprawl of nondescript buildings.
In another, James captured an old man looking out over Pudong district in Shanghai.
"He just looked really out of place. Kind of your archetypal countryside old Chinese guy I guess. Everyone else was a tourist or city Shanghainese."
Pudong, which up until the 1990s was mostly marshes and rice paddies, now houses modern skyscrapers including Shanghai Tower, the world's second-tallest building.
"I quickly made a double exposure of him and the view before he had time to notice and change his gaze," says James. "I liked the way it combines the new and old China in one image."
In the age of digital photography and apps like Fused, the once time-consuming and expensive process, can now be easily replicated.
And while photographers have long been playing with multiple exposures, James' distinct style of pairing up people and cities has certainly been influential.
Below, James discusses his work with CNN Style.
CNN: Why wasn't the double exposure technique more popular when you first began playing with it?
James: The technique has been done since really, the beginning of photography. But you wouldn't see it much because it was hard to control what image you were going to get and there wasn't a strong design element to it. It was seen as a gimmick.
I had used it a couple of times in music photography but there wasn't a trend for it. But when I started to work with cityscapes, straight away, it looked fresh. You had this first figure -- dark, with sky behind it. So, you had all this negative space. There weren't random things crashing in together.
CNN: Is height a deciding factor? Are the tallest cities the best to shoot in?
James: You have to find the right city, with the right scale of volume. With commercial commissions, I have had to shoot in San Francisco, Singapore, Hong Kong, but sometimes these cities don't have the same impact of scale, or the buildings are mismatched, at different heights.
But when you get up high in Tokyo, Bangkok or Shenzhen and as far as the eye can see, the buildings are all above a certain height.
CNN: As a professional photographer, how do you feel about the accessibility of the industry now, with camera phones and digital cameras?
James: It feels like everyone has strong visual knowledge. Everyone is their own storyboarder. We're all creating our own magazine, our own videos, our own content. But the level of imagery now, it's generic -- you see trends quickly come in and out. It has upped people's game but it's also like junk food. It's harder to grab people's attention, harder to stimulate them.
CNN: Your particular style of combining cities and silhouettes, which you began practicing in 2006, has been appropriated by other photographers. Google 'double exposure' and a flood of similar images come up. How do you feel about this?
James: It's a visual trend that I saw really taking off online a few years after I made my initial images in Tokyo in 2006. From around 2010 onwards I really noticed double exposures becoming a common place visual on the internet, in stock libraries and in advertising.
I guess some of that is driven by commercial factors, to make money and some of that is purely for creative play -- people making those images in camera, Photoshop or via apps because they can make an easy eye catching image.
As I said before, double exposure has been around since the beginning of photography, so that's fair game, but it does get annoying when I see a big brand make an advertisement that is really very close to one of my own images.
I've lost jobs before because a commission has had to be canceled just before the shoot because a rival brand released advertising that to all intents and purposes looked like I'd shot it.
I've also had people in the industry contact me saying that they worked on shoots where my photos were used by the art directors as their references for the storyboards. That gets a bit annoying as you think, 'why not pitch the job to me' rather than just have another photographer copy it.
But I guess that's the way the industry works and you can either accept it or try to fight it through a lawyer.
CNN: Clients -- both commercial brands and publications -- have approached you on the back of this series. What do you think the effect of double exposure conveys? What about it, for example, gets the Smithsonian interested, but at the same time, gets a big name brand, on board?
James: I think these images work on a purely visual and design level, but they also have an open ended quality that is neither negative or positive, but rather voyeuristic, with the figure looking detached yet part of their city.
This seems to appeal to a wide range of clients wanting to tap into that feeling.
CNN: What are your future plans for this series?
James: I've been making these images now on and off for over 10 years and recently I've had some gallery and publishing interest, so it would be good to bring it to a close with a series of prints and to publish it as a series in some form.
For more of James' photos, follow him on Instagram or visit his website.