You Gotta Have Blue Hair
aka: Bluenette

http://static.tvtropes.org/pmwiki/pub/images/tvt_curtainsmatchthewindow.jpg
Blue, purple, green, no hair dye required.

"And for some reason, I got blue hair. You gotta have blue hair."
Strong Bad (describing his anime counterpart, Stinkoman), Homestar Runner, "Japanese cartoon"

Though there are plenty of ways to differentiate characters from each other, one of normally limited utility is hair color. Human hair has a limited amount of variation, after all, not enough to make everyone on a half hour show once a week easily distinguished. Thus, this trope was born, so that artists could use the full spectrum of color. It's so common that it's mostly considered an Acceptable Break from Reality now.

This is especially common in anime, where characters often have impossible hair colors. This started with manga series that used distinctive colors on the covers to make characters stand out, even though they all had either dark or light hair in the actual black-and-white pictures; anime brought it to the screen and made it a standard part of character designs.

There are several reasons why artists do this. The first, noted above, is to help distinguish characters from each other, as with Anime Hair. It may be done to indicate character personality, such as an Emotionless Girl with blue or white hair. It may indicate that a character is unique, if they are the only one in the cast with their hair color. Or it may be done just to suit the artist's taste for variety. In some cases, artists may use Power Dyes Your Hair to explain how a character gets unusual hair when otherwise trying to be realistic in their hair color choices. Also not uncommon is that the Curtains Match the Window.

Some specific colors have subtropes which ascribe certain character traits to them: such as a blue-haired girl being shy, a pink-haired girl being cheerful or passionate or sweet (take your pick), and a white-haired young-man being evil.

A subtrope of Hair Colors. Hair Color Dissonance is when hair is depicted as an odd color, but is supposed to be a normal color (e.g., powder blue standing in for grey); specifically, when hair of a very dark shade of blue or purple is supposed to represent black hair, that's Purple Is the New Black. When the hair color is realistic but is not justified by the setting, that's Implausible Hair Color. For characters with impossible hair styles, see Anime Hair.

See also Amazing Technicolor Population and Mukokuseki.

Examples

    Comic Strips 

    Pinballs 

    Web Animation 
  • The Trope Namer, Homestar Runner, spoofs this when a fan named James asks what Strong Bad would look like as an anime character. Strong Bad decides that he'd be shiny and have huge green eyes, cooler boots, and blue hair ("You gotta have blue hair."), for some reason. Humourously, on one main page, scrolling over "Store" gives 1-Up (Homestar Runner's anime counterpart) blue hair.
  • In Mighty Magiswords, Prohyas has light blue hair and Vambre has violet hair.
  • Acedemy Sugoi Seiun has characters with bright pink, blue, yellow/orange/red (at the same time), and purple hair.
  • Eddsworld had Laurel, a one-time character in the "Movie Makers" episode.

    Real Life 
  • The celebrated "Glowing Green Monkeys", who were created by gene-splicing lab monkeys with bioluminescent sea creatures. Their hair only glows under fluorescent light, however, and look more of a dull greenish-brown under normal conditions. Bioluminescent pigs, on the other hand, are bright yellow.
  • A potential result of overexposure to cobalt or indigo dyes during industrial processes.
  • Purple squirrels have been showing up around the world. Whether or not it's some sort of prank is unknown. Maybe it's a commentary on the job market.
  • Can be invoked using hair dye.

Alternative Title(s): Amazing Technicolor Hair, Impossible Hair Color, You Gotta Have Colorful Hair, Bluenette, Impossible Hair Colours, Impossible Hair Colors, Screw The Rules I Have Green Hair, Technicolor Hair

http://tvtropes.org/pmwiki/pmwiki.php/Main/YouGottaHaveBlueHair?from=Main.Bluenette