Elemental Man. Other characters have included Green Arrow, the Superman Family, the Teen Titans and the Elongated Man. In 2018, Screen Rant highlighted, "publishers and retailers traditionally ignore the sales of trade paperbacks when it comes to deciding whether or not a specific title is doing well. For decades, the single issue has been king, even though those sales figures are far from helpful. [...] Trade paperbacks are increasingly important as a marker of what sells, with 2016 seeing a 12% jump in trade sales over 2015 - a period when single issue sales fell. Even 2017, which saw both trades and single issue sales fall compared to 2016, trades were down 9.38%, compared to single issues dropping 10.4%". In 2019, Bleeding Cool emphasized, "in recent years, collected issues/trade paperbacks are more popular and profitable than monthly comic book periodicals. As single issue sales have consistently plummeted, trade paperbacks and graphic novels have filled in the gaps. From 2013 to 2018, graphic novels were the highest-selling format for comic books". According to industry reports, "the massive shift to graphic novels as the preferred format for comics continued in 2019 bringing sales in the book channel above the comic store channel in North America for the first time in the history of the medium" and that "the sales of graphic novels were growing faster in the book trade than in comics shops". Comics creators' mainstream success While many comic book artists and writers had become well known by their readership as early as the 1940s, some comics creators in the late 1980s and the 1990s became known to the general population. These included Todd McFarlane, Neil Gaiman, Alan Moore, and Frank Miller. Some, such as Gaiman, went on to write critically and commercially successful novels. Others, like Miller, became Hollywood screenwriters and directors. Conversely, film and TV directors and producers became involved with comics. J. Michael Straczynski, creator of TV's Babylon 5, was recruited to write Marvel Comics' The Amazing Spider-Man and, later Fantastic Four filmmaker Reginald Hudlin became the writer of Marvel's Black Panther. Joss Whedon, creator of TV's Buffy the Vampire Slayer, wrote Marvel's Astonishing X-Men and Runaways, among other series. Richard Donner, who directed the Superman films of the 1970s and 1980s, became a writer on the Superman feature in Action Comics in 2006, co-writing with comics writer (and Donner's former production assistant) Geoff Johns. Paul Dini, producer