Origin
Lex Luthor uses a ray gun to rearrange molecules, the bait intersects with the rays from an experiment being done in the same area to split neutrons.
This incident copies Superman, creating another Superman, but in a monochromatic pattern and with an evil personality. Negative Superman and Superman repel each other like magnet poles. At one point Superman forces combat with Negative Superman and the reaction ends up making him absorb the evil copy.
Creation
Negative Superman was created in 1962, by Ed Herron and Jim Mooney, in World’s Finest Comics #126.
Negative Superman resurfaced in 2012, at the hands of Art Baltazar and Franco Aureliani, in the comic book Superman Family Adventures #4.
Other Versions
In Superman Family Adventures #4, Negative Superman reappears, when Titano emits bursts of red kryptonite from his eyes, separating Superman into two, one good and one evil. Reminiscent of Superman III, the 1983 movie.