John Byrne' revision of the Superman character in 1986 reduced the character's abilities. This was designed to make it easier for writers to come up with suitable challenges for the hero and to eliminate or reduce those powers that had become too sensational or unbelievable for modern audiences. Emphasis was placed on yellow sun energy as a source for the character's powers. Superman's origin story was altered so that his powers developed gradually as his body absorbed yellow sunlight, and stories such as the Final Night series depicted the character gradually losing his powers when deprived of the sun's energy. When Superman's reserves of solar energy were depleted, as in Infinite Crisis or the Death of Superman story arcs, he required an extended period of time under a yellow sun, or some type of artificial solar enhancement in order to recharge.
Superman's strength was reduced to the point where he could still move tremendous amounts, but the character no longer had the ability to move planets. His speed was also reduced so that he could not come close to the speed of light. While still capable of surviving a nuclear explosion, such events would severely weaken him. Superman's sight, stamina and breath powers were also similarly reduced, and the character also required an oxygen mask for prolonged travel in space or underwater. His mental abilities were also curtailed to the point where intelligent humans, like geniuses Lex Luthor or Batman, could outsmart him. The powers of super-ventriloquism and super-hypnosis were not generally used during this period, although it was never stated whether they had been eliminated or not.