Goku during the Freeza Saga (very pale):
Goku at the end of the Boo Saga (a bit darker):
Goku at the end of DBZ (a bit darker still):
Goku in GT (noticeably darker):
Goku in the Goku Jr. Special (practically black):
Ever since I had finished DBZ and DBGT, this has always been in the back of my mind: Why is Goku's skin gradually darker as the series progresses? By the Goku Jr. Special, it's very clear that he is obviously meant to be darker, and that it isn't just some subtle ink changes... you can definitely tell he's way darker than Goku Jr.
Could it have something to do with age? I've noticed that Vegeta's skin seemed to become darker as time went on. But Goku even had really dark skin when he was turned back into a kid at the beginning of GT, and it's obvious he isn't meant to age by the Goku Jr. Special, yet he's practically African.
To your knowledge, has this ever been addressed?