Batou667 said:
- When Westerners or other foreigners are portrayed in manga/anime, they often look quite markedly different. The most extreme example of this would be the generalised "gaijin" or foreigner stereotype with tanned skin, light hair and coloured eyes (i.e., different in every way to the Asian characters).
- And finally, some manga/anime is actually drawn in a more realistic illustration style, such as Katsuhiro Otomo's Akira, and features characters who all have jet black hair and Eastern features.
Bizarrely you just covered two things there that I was going to use as a COUNTER argument... (against the OP, not yourself - though my points are maybe tangential to yours)
EG The little kid in Love Hina (I forget her name) - supposedly american but with a touch of african in her. Easily the darkest skinned (whether it's natural, or a tan, who knows - but she seems to keep the same tone through winter so let's assume she's half-cast) with strange bleach-blonde hair... presumably that's for keeping enough contrast in her character design that she doesn't end up blending into certain backgrounds. She's supposed to be the obvious gaijin, but given that she seems to have caught up on japanese culture and language pretty quick (and almost always wears a sailor fuku) perhaps any obviousness to a native viewer, besides the skin tone, is in her accent or something?
Or Ed in Cowboy Bebop, if you count ginger hair as being roughly equivalent to blonde... though she's just one member of a quite diverse series cast and far from the darkest (plus, her exact origin is a complete mystery - we must assume the Gaijin thing because she's just so plain weird, that its the trope niche she occupies). Even Jet, Spike and Valentine strike me - as a brit by upbringing and heritage - as being asian, but of different backgrounds within that continent, and they're joined by plenty others of every race.
Oh, and ... Joker for crying out loud? (Who suffers one or two in-dialogue racist jibes, and doesn't respond ever so happily to them... but all in all is simply a character in his own right who happens to be a surprisingly fat black guy)
Or the two or three other token foreigners in Akira, who are quite easy to spot vs the general cast of actual tokyo-region modern japanese?
Anime/manga has had quite a lot of whitewashing down the years, for the obvious technical and cultural reasons, but it's untrue and unfair to say that all characters are white. It doesn't even take into account the actual ethnic variations within Japan itself that are often represented - some are paler with dark hair, but you do get some non-gaijin ones with darker skin and lighter hair (brown, or indeed blonde), showing they're of a different region and heritage than the typical tokyo box-room resident. I forget the actual term used for them, but there is one. If I get bored (ha!) I may google it
Even Studio Ghibli - with a long, somewhat questionable tradition of having entirely aryan character lists - has used that last one from time to time. Ashitaka's part of that ethnicity for a start, and it's possible San is at least partly so, inamongst the more dominant, warring fair skin/dark hair tribes.
- Manga is traditionally drawn in black ink first and coloured later, or not at all. To help differentiate between the characters, and to add "emotion", the artists responsible for colouring would often make quite bold choices for hair colours. Trying to depict characters as being racially diverse was never the intention.
So as a lot of production of both still comics and moving cartoons shifts into the digital realm - at the very least for the previously very expensive postproduction (IE inking, painting, tweening) if not entirely (IE including the original sketches) - does that mean we'll see less "whitewashing"? It completely obliterates the main thrust of that argument. Doing white-on-black, or using various shades of zipatone is as easy as plain black-on-white (and certainly simpler/cleaner than, say, drawing in white on black paper, making a xeroxed negative, or hand-shading/toning your characters, which one assumes Otomo only bothered with because he/his helpers were already drawing so many hugely detailed backgrounds, why not have a B-lister with dark skin too?), and indeed if you're producing the final copy in colour, just as easy or difficult as making everyone's outlines, fills and shading any colour you like. The great many artists making full colour webcomics in their spare time, including manga ones, don't seem to regard it as a problem.