There had been some “squint and you can see them” individuals in group shots earlier in the storyline, but the Sergio Leone-style “showdown” page showed the Kryptonian-equivalent of Africans and Asians. (Preview of Superman #683 here.)
“In issue #239, a two-page map showed that Kryptonians of color had an island all to themselves, which is pretty embarrassing,” says Mark Waid, Boom! Studios Editor-in-Chief, occasional DC Comics writer, and pretty much expert in all things Superman. “I cringe to tell you this, but the Kryptonians of Color were all on ‘Vathlo Island, Home of a Highly Advanced Black Race.’ It wasn't until the mid-70s, when more ‘World of Krypton’ back-up stories ran more regularly, that we really saw any ethnicity whatsoever on the planet.”
While he’s not sure of how exactly Krypton's population diversified, Waid figures that it had to do with E. Nelson Bridwell, the assistant on the Superman books at the time. “He took a special interest in ‘caretaking’ the history and fictional culture of Krypton,” Waid says. “More than anyone else who ever lived, Nelson knew that world.”
Much like other mono-cultural planets of the Golden Age of science fiction, Krypton was a product of its time. “A lack of ethnicity was an eror of omission, and I'm not sure given the time that it's fair to call that ‘racist,’” Waid says. Superman creators Jerry Siegel and Joe Shuster, and all those who followed in crafting the Superman legend were, indeed, simply following the traditions of the Golden Age of Science Fiction, when one world always equaled one culture, maybe two if they were at war because the plot demanded it.
Remember, as absurd as this sounds in an America finally enlightened enough to elect a black man as President, the Civil Rights Act wasn't passed until 1964. The gradual recognition of all races and ethnicities across all of pop culture, comics included, really didn't start to blossom until the late 1960s.
Yes, Superman was weirdly late to that party — the first African-American even in a Superman story, and it's from the summer of 1970. But again, and not to make excuses, that delay was just creative inertia in action. After the start of a diverse Krypton in the early ‘70s, it was left up to creators and editors to make sure that Krypton was racially diverse, and it was occasionally shown to be — if the story allowed. Throughout its rather ignoble history, Vathlo Island remained undeveloped and unexplored by writers, which is both good and bad, probably. One interesting idea that was floated in the very brief mention of Vathlo in Krypton's history was that there was no slave trade on Krypton, which is why races didn't really mix — or at least why some of Jor-El's best friends weren't black.
But with “New Krypton,” story architects Geoff Johns, James Robinson and Sterling Gates have been working to merge all aspects of Krypton that have been shown over the years, making all the visions and versions into a workable whole — including the fact that the planet was racially diverse — and hopefully without the segregation of Vathlo Island. Here's hoping for a more colorful Krypton.