Board Thread:Naruto Discussions/@comment-28939725-20161116235549/@comment-4912646-20161118015558

We clearly see (in earlier coloured art anyway) that Naruto's chakra is in fact yellow, and Kurama's is in fact red, so it definitely seems to be more than a metaphor. Though there's also the argument that yellow may be everybody's chakra colour in the manga, just like blue is the generic colour in the anime. Sadly, Naruto and Kurama are the only ones whose chakra colour was actually mentioned in dialogue, so we're left with only a handful of coloured manga pages to try to figure anybody else's out. And these days Kishimoto seems to generally use the anime's colour scheme rather than his own (Naruto's Rasengan is blue and his Chakra Mode is orange tinted, etc.) but at least Sasuke's chakra retained its distinct dark blue/violet colouring right until the end.