Digital disruption has upended virtually every corner of publishing, but in the world of comic books, something curious is happening: Print sales are thriving alongside the rise of their digital counterparts.
Print comic book revenues have been on the rise in recent years, even as digital comics' sales boom. Print receipts have held up at a time when publishers have introduced all-you-can-download subscriptions that offer thousands of comics for a flat monthly or annual fee.
In 2014, digital comics revenues excluding unlimited subscriptions reached $100 million, according to ICv2, an online trade magazine that tracks comic sales and other trends. That was up from just $1 million seven years ago, when ICv2 started collecting data.
Meanwhile, the North American market for print comics grew from an estimated range of $650 to $700 million in 2009 to $835 million in 2014, according to ICv2 and the Comics Chronicle. That includes sales of single issues at comic shops and newsstands, as well as book channel sales of trade paperbacks, or collected volumes of comics.
There are signs digital comics are butting up against the law of large numbers. Sales growth slowed in 2014 to 11 percent, down from 29 percent in 2013 and 180 percent in 2012. In the coming years, it could be more difficult to keep growing the readership.
Taken together, however, it suggests the internet age hasn't wreaked the same type of havoc on comics that it has on sectors like music and print media.
"We have not seen any cannibalization in sales either in periodical comics or trade paperbacks," Gerry Gladston, chief marketing officer at New York City–based Midtown Comics, one of the industry's leading retailers.
Compare that to other print media.
Weekly circulation of newspapers is down 17 percent over the last decade, and advertising sales have plummeted more than 50 percent, according to Pew Research Center. Magazine ad revenue is forecast to see only minimal growth through 2019 on the strength of digital sales after five years of decline, according to PricewaterhouseCoopers.
To be sure, comics are relatively new to the digital domain. Creators have been uploading web comics since the rise of the commercial internet in the '90s. However, mainstream comics didn't migrate online in any significant numbers until smartphones and tablets became commonplace.
Following its launch in 2007, comiXology established itself as the dominant player in digital comics distribution — largely on the strength of its Guided View technology, which offered a more fluid reading experience than previous apps had afforded. Marvel Entertainment and DC Comics adopted comiXology's platform in their digital storefronts, and in 2014, Amazon purchased the company for an undisclosed amount.
Marvel also offers access to an archive of more than 17,000 comics for $69 a year through its Marvel Unlimited service. Comics enter the archive a few months after they hit the stands, making it akin to a Netflix for Marvel Comics.
Last month, ComiXology launched its own subscription service, comiXology Unlimited, that features thousands of comics from publishers like Image Comics, Dark Horse Comics and a number of other small and midtier publishers.
Unlike Marvel Unlimited, comiXology is explicitly designed to introduce readers to new titles and get them to buy single issues or trades. So a subscriber can read the first few story arcs in Image's acclaimed "Walking Dead" title — but they'll have to pay up to read the rest of the series.
So why exactly aren't these services killing off print comics? It may have something to do with the collectible nature of the medium, according to Gladston.
"After tasting digital comics, many fans go back to 'the real thing,' a comic book they can hold, collect, archive, share and have creators sign," he said.
John Jackson Miller, a writer who tracks comic book sales on the Comics Chronicles, has another theory. "The audiences for print and digital overlap some, but not a lot," he told CNBC.
"Digital comics serve a customer base that is somewhat different: either located far from a comic shop or unwilling for space reasons to hold on to a large physical library," he added.
While no one has yet done the research to determine whether digital downloads drive more print copy sales, there is a positive — if indirect — relationship, Jackson Miller said.
Just like trade paperbacks give single-issues a second life as bound collections, digital comics take "some of the pressure off the individual comic book by adding an additional revenue stream for basically zero expense," he explained.