The Secret to the Supermen's Super-Secret Identity

One of the oddest concessions in the mythos of the Supermen is how they disguised themselves by wearing a simple pair of glasses and a displaying a mild-tempered alter ego. It turns out, more was involved.

For the Earth-One Superman Kal-El, it involved his use of eye lenses for his glasses, made of Kryptonian glass remnants* from the space craft that brought him to his adopted world. Through these glasses, his super-will power mesmerized those who saw him, making them perceive him as he wished them to... as meek reporter Clark Kent!

For the Earth-Two Superman Kal-L, it involved an ability only he possessed, whereby he was able to mold his facial features** in any shape he desired. This allowed him to transform his gallant face into that of meek reporter's. How Kal-L could mold his invulnerable face in such a manner is unknown, but is perhaps a native born Kryptonian ability as many of his superpowers were those common on his homeworld.

Of course, Kal-El didn't realize his glasses produced this effect until years after he first adopted his Superboy alias. While his adopted parents Jonathan and Martha Kent, and his close friends such as Batman and his fellow Justice Leaguers, saw him as both Clark and Superman... none of them revealed that his appearance changed when donning his glasses. Apparently this was a subconscious effect, which even fooled telepathic fellow Leaguers Aquaman and J'onn J'onzz.

As for Kal-L, since he began his costumed career as an adult having thoroughly trained with his growing abilities, he would have knonwn that his malleable face was sufficient to protect his double identity. And apparently, this is the same technique used by his cousin Kara aka Power Girl, while using her Karen Starr alter ego. As to how Power Girl's counterpart and Kal-El's cousin Supergirl was able to disguise her connection to Linda Lee Danvers, with only a brunette wig, is unknown.

* Detailed in Superman #330 - during this tale, while battling Batman foe the Spellbinder, Superman learned of his glasses' unique attribute

** Detailed in Superman #253 - which also explained in 1972 (for the first time) that Clark and Lois were married, six years before the story of their marriage was told in Action Comics #484