So you've just watched The Film of the Book of your favorite series. And it was good. There was one detail, however, that they missed. The main character's hair, blond in the original, was brown, and the wacky sidekick's hair was a darker shade of yellow than usual. His eyes went from blue to brown. And why was the villain's jacket orange?
At least that's the most common version of this trope. For some reason as a work moves from one medium to another, characters' hair and eye colors will be changed, costumes will be toned down, color schemes will be swapped about or adjusted. While occasionally there may be a justification for this (as may be the case for works which were originally in Black and White or monochromatic), more often than not it is just a random change made as a work is adapted.
One particularly common adaptation dye job for costumes is that more often than not, in a movie adaptation, everyone now wears black. (This is mainly due to Rule of Cool and black just looking good on camera.) Conversely, in animated adaptations, colors are often brightened, diversified, or flattened, to make things easier on the character artists and for maximum visual clarity on a small screen.
It is unclear why matters of color are one of the things executives target first, but it can cause problems down the line if any of the original color choices had symbolic meaning.
This is usually excused in the case of Legacy Characters. Usually. It's also generally justified when casting for a live-action version of a work, as most casting directors favor, you know... acting ability over resemblance to the original character. And as shown in the examples, live-action also has different aesthetic considerations to animation, meaning different choices must be made for things to look good. But some fans bring it up regardless.
Related to Spell My Name with an S. Can be related to Race Lift, if the skin color changed with the hair. Though the visual effect can be similar, this is not related to Palette Swap. If the character's entire hairstyle was changed instead of — or in addition to — the color, see Adaptational Hairstyle Change.
Dyeing for Your Art can avert this, though it won't always. See also Hair Color Dissonance, Early Installment Character-Design Difference, Inconsistent Coloring, Suddenly Blonde, and Sudden Eye Colour.
