The Picture of Dorian Gray: Dorian Gray is an angelic-looking blond in the novel, but its seems to be much more common for films to portray him as a brunette. The classic 1945 film version starred the dark-haired Hurd Hatfield, and subsequent dark-haired Dorians are probably due to directors going off of that film (and/or assuming that Dorian must look like a Byronic Hero) rather than actually reading Wilde's novel.
In the book Lord of the Flies, Simon's hair is black. In the 1960's film adaption the character has bleached blond hair.
In the adaptation of the E.M Forster story Maurice by James Ivory, Maurice is blond rather than dark-haired, even though (as David Leavitt wrote in his introduction to the 2005 Penguin Classics edition of the book) "Forster makes so much of Maurice's hair being black. For Forster, black hair connotes virility."
Frank Hardy's hair is described as dark and usually drawn as black on the book covers. In the 1970s TV Adaptation The Hardy Boys/Nancy Drew Mysteries, it's inexplicably golden-blonde.
The eye colors of both brothers also fall into this. In the books, Joe Hardy is blue-eyed. In The Hardy Boys/Nancy Drew Mysteries Frank has the blue eyes, Joe's hazel, and the show makes a special point of Frank's eye color in several episodes. Not that anyone's complaining, mind...
In one of the games, Betrayal at Krondor, the magician Pug - who in the books is described as having dark brown hair and a beard and usually wearing a black robe - has shoulder-length blond hair, is clean-shaven, and wears a white robe. Similarly, Locklear is described as having wavy blond locks in the book, but in the game his hair is chestnut brown. This is even lampshaded when he meets an old friend.
In the graphic novels, the elf queen Aglaranna - who is described as having reddish-gold hair that contributes to her overall soft and angelic appearance - is given bright scarlet hair.
Armand is described as having auburn hair. In The Film of the BookInterview with the Vampire, he has exceptionally dark brown or black hair. The idea of costuming Antonio Banderas as a "Botticelli angel" would have been patently ridiculous.
Lestat, who in the novels has very long and blond hair gets a dark pseudo-pageboy cut in the Queen of the Damned movie. And Marius who likewise was supposed to be long-haired blond gets short, slick black hair in the same movie.
In the original book version, Murphy is a tiny blonde. In the TV adaptation, she's a tall brunette. She was Irish-heritaged in the novels and described as the cheerleader's younger sister or some such nonsense. In the series, she was Mexican-heritaged and not at all as cute as the book version was.
Susan and Murphy look like each other's book counterparts because the actresses were determined to be much better for each other's roles than the roles for which they were initially cast.
Not much is said about Coraline's appearance in the book, except that she has hazel colored eyes, is short for her age, and has brown hair. In the movie her eyes are the same as in the book, she has freckles on her face, she is rather tall for her age, her hair is short and blue, and she always wears blue nail polish. There's a blink and you'll miss it shot of a photo showing Coraline with brown hair, implying she dyed it.
Coraline in the graphic novel has parted light brown hair that goes past her shoulders. In most official illustrations of the book Coraline has darker hair in a bob haircut, though the length varies.
Bill has red hair in the book, which is one of the reasons why the also red headed Beverly is attracted to him. In the 90s version Bill is played by the late Jonathan Brandis who had light brown-blondish hair.
Bill was also balding as a adult in the book, but ironically has freaking a ponytail as adult in the 90s adaptation.
Beverly herself has pronounced red auburn hair in book with it being mentioned numerous times but both actresses who play her as a kid and adult are brunette. It gets even worse as Bill’s wife Audra has red hair like Bev in the book (which was the reason why Bill was attracted to her) but Audra has dark hair in the Miniseries.
though he has darker hair in the book, Richie is the only one who has red hair thanks to being played by Seth Green as a kid but as a adult he becomes a brunette with a moustache which was not present in the book.
The titular Monster Clown is also subject to a dyejob as Pennywise’s clown suit is actually silver white in the book but Tim Curry’s clown suit in the Miniseries is yellow, green and purple. Though to be fair Muti-colours are more common for Real Life clowns.
It (2017) is more accurate to book despite Bill again having brown hair instead of red, Pennywise’s clown suit is sliver like in the book though his fluffy buttons are red instead of orange. Most importantly Beverly hair is redheaded at last, the only change being she cuts her red long hair to short red hair after her creepy dad strokes her hair; which is a good justification.
Chris Hargensen is an olive-skinned brunette in the books, but Chris is played by blondes Nancy Allen and Emilie de Ravin. However the 2013 version had the naturally blonde Portia Doubleday dye her hair brown for the role.
Sue Snell is blonde in the books. In the 1976 film she's played by redhead Amy Irving. The 2002 film also gave the character a Race Lift and had her played by mixed race Kandyse McClure. She's blonde in the 2013 film.
Tina Blake is described as a redhead in the book. She's a brunette in both the 2002 and 2013 films.
Norma Watson is blonde and is played by blonde PJ Soles in the 1976 film. However, the 2002 film casts the brunette Meghan Black.
There is some confusion about Tycho Celchu's hair color in the X-Wing Series. In the comics, it's almost always blond. In the novels, by the three authors who will include him, sometimes it's blond, sometimes it's pale brown. It's never been directly addressed, but fans generally speculate that since these discrepancies never take place very soon after each other, it's because he has had time to either dye it or allow it to be bleached by sunlight.
It is mentioned several times in the books that Lucy Pevensie is blonde. She's a brunette in the films. Funnily enough, Georgie Henley's hair was apparently lightened for the film..
Prince Caspian was also a blond in the books, but brunet in the film.
Edmund and Peter, who have blond and dark hair respectively in the books, but their hair colors are reversed in the movie, Edmund being dark-haired and Peter fair-haired. The fans seemed to like the movie version better, due to Edmund's Anti-Hero status that fitted really well with his dark appearance, which was in contrast with the other Pevensie children, who were more fair. Skandar Keynes was chosen especially for Edmund's role, because the director considered him to be darker than his co-stars; Eerie Pale-Skinned Brunette, mischievous, snarky and the facts that he wore more black and listened to heavier music created his Anti-Hero image on the spot.
Of the four Pevensies, the only one to keep her original hair color in the films is the dark-haired Susan – the one who, in the books, eventually abandons Narnia for "lipstick and nylons and invitations." If the complete series had been adapted, as was presumably intended at first, this would have meant that the two lighter-haired siblings, Peter and Lucy, were ultimately the more purely good ones, while the two darker-haired ones, Susan and Edmund were the two darker characters too. But as it turned out, the film series was cut short before it could reach Susan's fall from grace.
The Pauline Baynes illustrations, which were commissioned specially by Lewis himself and have been used in many editions of the text, portray Lucy with black hair and Susan with lighter hair, despite that Lucy is stated to be blonde, and Susan is black-haired.
The 1980s BBC adaptation also has a blondish-haired Peter and brunette Lucy. It's version of Susan is blonde too.
Zaphod is blond and Ford is redheaded. In the TV series, they both have dark hair, and in the movie, Zaphod is blond again but Ford is played by Mos Def. (In the original radio serial, hair colours aren't mentioned, being rather irrelevant on radio.) Mark Wing-Davey, who played Zaphod on radio and TV, is quoted as saying that he said he thought Zaph was "a blond beach bum" (with the implication that he'd have been quite happy to wear a wig), but the producer/director (Alan Bell) wasn't listening to anyone involved in the radio show.
The illustrated book also has a dark-haired actor playing Zaphod. This gets lampshaded: the description of him as blond has a footnote added to it saying that anyone perceiving him as otherwise is probably suffering from Mad Human Disease.
In the book series, Trillian was described with dark hair. When the series came to television, she was played by blonde American Sandra Dickinson. This was done on advice of Douglas Adams himself, who liked Dickinson on the role.
In the Sword of Truth book series, Darken Rahl is described as having distinctly blond hair, but has black hair in Legend of the Seeker. Flashbacks of his father Panis Rahl have him be with entirely white hair.
Boromir and Faramir are described as having dark hair. For the movies they were given light brown hair, bordering on blond. This is purely because they needed a way to make Boromir and the dark-haired Aragorn instantly visually distinguishable, and putting Boromir in a Viking helmet had been ruled out.
Legolas has dark hair in the books, depending on your interpretation.
Sam and Merry both have fairly blond hair in the films, whereas in the books blond Hobbits are a rarity.
Frodo had blond hair in the books. This is even mentioned as a way to distinguish him from other hobbits, but in the films he got brunet hair that borders on black in some scenes.
Kíli in The Hobbit film trilogy has dark hair in contrast to the blond hair he originally shares with his brother Fíli in the book.
Tauriel's counterpart in the book (the unnamed captain of the Elven guard) is unlikely to have had red hair, going by Tolkien's lore.
Dwalin had a blue beard in the book, but has a dark brown beard in the films.
In the Howl's Moving Castle book, Sophie has "reddish straw-colored" hair. In the animated movie, she has brown hair. Also, in the scene where Howl throws a fit because Sophie messed up all his hair potions, his hair was supposed to go from "mud" to the "reddish straw" thing (but pinker), but ended up getting from a yellow-blond to... wet-colored yellow-blond. Then to black because he throws a fit.
Arya has black hair. In the movie, she inexplicably has blonde hair. This, when combined with her human features, makes it impossible to tell she is an elf (except for the fact that early in the film it is directly mentioned she is, which just reinforces the idea that otherwise, nobody would work that out). The changes of hair and ears were reportedly because the director feared a confusion with The Lord of the Rings' Arwen. Which is especially funny in the latter case, as Tolkien never said his elves had pointed ears in the published texts (the only hint comes from a tiny note in an etymological dictionary about his ConLangs).
Eragon. The books described him having brown hair and eyes, but in the movies, he is blond-haired and blue-eyed.
Murtagh is supposed to have brown hair in book 1. In the movie they gave him black hair. In book 3, his description backs up the movies.
Princess Ozma's hair is described specifically: "tresses of ruddy gold, with a slender jeweled circlet confining them at the brow." However, in John R. Neill's illustrations, her hair is either colored brown or black. Whether this is intentional (to distinguish Ozma from the blonde Dorothy Gale) or simply a printer error is debatable, but most modern Oz fans, authors, and illustrators portray her with brown hair or, rarely, black. The "slender circlet" became much thicker in the illos, and was attached to a crown on top of her head. Ozma's hair was only described once, on her original (re)appearance. After that, well, maybe The Wizard Did It. Ozma was blonde in Return to Oz (though not a reddish blonde).
Dorothy may or may not count as an example in the classic 1939 film. Her hair color is never mentioned in the books: the original illustrator, W.W. Denslow, gave her light brown hair, but John R. Neill, as mentioned above, made her blonde. Onscreen, she's played by brunette Judy Garland with her hair dyed auburn.
The slippers were silver in the original book; they were changed to red to take advantage of the new colour technology. Many other adaptations keep them silver, often became they're unable to use the more iconic red design due to copyright issues.
Glinda is described as a redhead, however in most adaptations besides the MGM film she is a blonde. In at least Wicked's cases this is because MGM has a veto on Glinda as a redhead, though it works in their favor due to being able to portray Glinda as initially seeming like a Dumb Blonde and also because it clashes her with the black haired Elphaba.
The Wicked Witch Of The West has a Sickly Green Glow in the MGM film. In the books, it's never mentioned what her colour is, however she lives in the part of Oz where yellow is the main colour (and her castle in decked in yellow). Most likely, she has a yellow-based design. Wicked is based on the books but uses the MGM film's green skinned design. Official art depicts her with a normal, pale skin tone and a red-and-yellow outfit.
In The Worst Witch, Enid Nightshade went from being blonde in the books to having brown hair in the tv series. In the earlier television movie, Mildred (black hair) and Maud (blonde) both turned brunette.
Elena was blonde. In the TV show, she is played by the dark-haired Nina Dobrev.
This extends to Caroline, who was a brunette in the books
Alba from The Time Traveler's Wife is specifically and repeatedly described as having curly black hair. That's important because she is supposed to take after her father physically. Nevertheless, her movie version has straight blonde-ish hair.
May Welland in The Age of Innocence is a blonde (as well as blue-eyed), while Ellen Olenska is dark-haired. This is symbolic, as may s the "good girl", while Ellen is the "bad" one. But when the book was adapted for the screen, May was played by the brunette Winona Ryder, while Ellen was played by the blonde Michelle Pfeiffer.
Averted with the casting of Vivien Leigh as Scarlett O'Hara — despite the numerous references to Scarlett's black hair, a number of blonde and redheaded actresses were considered for the role, but ultimately they went for a dark-haired woman. Played straight with her eye color, however: Leigh's eyes were blue, whereas O'Hara's were green. The filmmakers made some bad attempts to disguise this, though.
Meggie's golden-red hair is referred to countless times throughout the novel "The Thorn Birds", but in the TV miniseries adaptation, she is played by the brunette Sydney Penny (as a child) and Rachel Ward (as an adult). Her daughter Justine is also a red-head, but played by the brown-haired Mare Winningham.
In Dracula the brides are described as one blonde and two brunettes. Many adaptations change one of the brunettes to a redhead to enforce the Blonde, Brunette, Redhead trope.
In Deltora Quest, Jasmine was described as having black hair, but has [[green hair]] in the Anime. Similarly, Lief was assumed to be a brunette, but became blond-haired in the Anime.
On the same note Doom has green hair as well, just in case it wasn’t super obvious he and Jasmine were related.
The eponymous character of Artemis Fowl has blue eyes initially. An eye swap with Holly in The Lost Colony gave him a hazel eye. In the (admittedly black and white) graphic novels his eyes are black.
In the first book of The Princess Diaries series, Mia is described as being "dishwater blonde" and after a makeover her hair is trimmed short. In the movies, she's played by brunette Anne Hathaway.
In Percy Jackson and the Olympians, Annabeth was described as having curly blonde hair. In the movies, she's brunette. She also has gray eyes in the book. Movie Annabeth has bright blue eyes. All demigod children of Athena were supposed to be blondes with gray eyes.
Percy was supposed to have black hair and green eyes, but he also turned into a blue-eyed brunet.
The TV series Jeeves and Wooster had a few instances of this. During the first season, the blonde Madeline Bassett was portrayed by a brunette. Both actresses who were cast as the platinum blonde Florence Craye were also brunettes. Finally, the hair of the actress who portrayed Bobbie Wickham during the first season could hardly be described as a vivid shade of red (or any shade of red unless you squinted really hard).
Sharpe had black hair in the books and was from London, but blonde YorkshiremanSean Bean was cast in the title role for the TV adaptation. Bernard Cornwell was sufficiently taken with Bean's portrayal that later books retconned Sharpe's accent and backstory, but there wasn't much he could do about the hair.
In The Prisoner of Zenda, King Rudolf, Rudolf Rassendyll, and Princess Flavia, like all the Elphbergs, have red hair; in the 1939 film, both Rudolfs are (probably) brunets (or at least one brunet, Ronald Colman) and Flavia has become "golden-haired goddess" Madeleine Carroll.
In Lloyd Alexander's The Chronicles of Prydain, Princess Eilonwy is a redhead and Fflewddur Fflam was described as having "straw-colored hair." The Disney version made her blonde in all sense of the word while ageing him thirty years and giving him white hair.
Averted in Walt Disney's Snow White and the Seven Dwarfs. Snow White has hair "as black as ebony," just as described by the Brothers Grimm, as well as brown eyes. However, there do exist numerous pre-production drawings from the film, which show that the Disney animators originally considered giving her blue eyes and blonde hair or red hair. It seems the artists had a hard time deciding on one of the standard three hair colors.
In the Twilight film Edward's "bronze" and reddish brown hair looks browner than described in the books. The manga keeps his hair reddish.
Tobias from Animorphs is described as blond at the beginning of the series. Then the model they hired to pose as him on the book cover turned up with brown hair, and the author started writing he has dirty-blond hair to make up for it. In the TV series adaptation, he has very dark brown hair.
Gossip Girl: Jenny was originally a brunette in the books. In the TV series, she is blonde.
Angelina Ballerina has white fur in the original books and first cartoon, but has pink fur in the CGI cartoon.
Blond-haired Chloe Steele and Nicolae Carpathia from the Left Behind book series got darker hair in the films.
Vanity Fair: The redheaded Becky Sharpe becomes a blonde in the 2004 film version.
Christine became a brunette instead of a blonde, probably so Sarah Brightman could play her.
The Lloyd Webber musical wasn't the first version to invoke this: Mary Philbin, who played opposite Lon Chaney in the silent film, was also brunette.
The costume designer may have actually had the silent film in mind, given that both silent movie!Christine and her stage musical counterpart aren't just brunette, but have cascading frizzy curls.
Meg in the original novel was brunette and became a blonde in the musical.
All of the above applies only to the original Harold Prince/Maria Björnson production of the musical, as seen in London and on Broadway. In the Hungarian production of the show, Meg is sometimes brunette. Chrsitine is sometimes blonde. It all depends on the actresses.
Enjolras should have blond hair, though many actors such as Michael Maguire do not.
Cosette should have dark hair, whereas in the 25th anniversary tour and Broadway productions and on the current London stage she is blonde. A lot of productions do manage to use a blonde wig for Fantine though.
Fantine is changed from blonde to brunette in the above adaptation, while the brunette Cosette once again becomes a blonde.
Eponine is dark-haired in most stage productions and the 2012 film, whereas Victor Hugo refers to the child Eponine as having chestnut/auburn hair, and describes her teenage self later in the story as having a "blonde pallor" – though the latter description might only refer to her sallow complexion, not her hair.
In The Kite Runner, Assef is mixed race (Afghan and white German) and is stated to be blond. In the movie he has black hair. Him being blond is a minor plot point in the novel, since he is said to be a Nazi who thinks that he is superior. His Nazism is downplayed in the movie, however.
The Mr. Men Show: In the original books, Mr. Quiet and Miss Magic were light brown and Mr. Lazy was light pink; in the show, Mr. Quiet is light blue, Mr. Lazy is green, and Miss Magic is orange.
In the movie version of Going Postal, Vetinari is blond. This is a strange example though; his hair color isn't mentioned specifically in the books but the general assumption is that he has dark hair and the illustrations certainly show that. So even if it wasn't actually a contradiction, it was still weird for many readers to see a blond Vetinari. (Especially as he was dark haired in the previous movie.)
In most film versions of The Great Gatsby, Daisy will be blonde and Jordan will be brunette. It's the other way around in the book. Although Daisy's hair is described in contrasting terms in the book, either as fair or dark. She may dye hard, or it may symbolize her elusiveness.
In the Warrior Cats books, Millie is a silver tabby. On the manga covers, she's pinkish-brown colored. The illustrator explained that when he got the character outlines, she was only described as a tabby, so he pictured her as rosy brown, didn't find out her real color until he had already colored the cover of the second volume. He discussed with his editor whether to change it, but they decided that it would be dull to have two gray cats next to each other.
Blanche Ingram is described as a dark beauty in Jane Eyre with black raven hair and olive skin. Several adaptations portray her as a blonde instead, presumably to contrast more with the brunette Jane.
Donald and Douglas arrived on Sodor painted black in the books, then were painted blue when the Fat Controller decided to keep both of them. They remained black in the TV series.
The Skarloey Railway engines were all (apart from Rusty the Diesel) painted red with blue stripes in the books. To help younger fans tell them apart, the TV series gave them different colours. Skarloey and Rheneas kept their original colours, but Sir Handel was blue, Peter Sam green, Rusty orange and Duncan yellow.
Guinever in The Once and Future King is stated to have jet-black hair, even though the narrator admits that she is blond in almost all other versions of the Arthurian legends, including the author's source materials.
In the book, Natalie Dashkov has black hair, in the film, her hair is brown.
Sonya Carp is a redhead in the books. In the film her hair is dark brown.
The blue eyes linked to seeing beyond in The Giver are not mentioned in the film, and the indicator is instead a Birthmark of Destiny. Although Taylor Swift and the babies who play Gabe retain their paler eyes, Jonas has brown eyes instead of blue.
Elena and Katherine were both originally blondes in the books. They are brunettes on the show.
Caroline is a red head in the book series, but is blonde on the show.
Bonnie is originally a pale-skinned, redhead in the books, but she is African-American with black hair and darker skin on the show.
In the film adaptation of the first book in the book series Percy Jackson and the Olympians, the main female character Annabeth, who in the book is stated often to be a blonde, is played by a brunette. Of course, this is only one of the vast number of changes they made to the plot, not least changing who the Big Bad is, but the Annabeth hair change is the only one that fits in this trope.
Grandmother in Flowers in the Attic has grey hair in the books (and it turns out to be a wig) but is red-haired in the film.
Umino and Nagisa both have purple hair in the Satou Kashi no Dangan wa Uchinukenai light novels. In the manga adaptation Umino has black hair while Nagisa has a dark brown. Nagisa's hair is also shortened in the manga.
In The Mortal Instruments, Camille Belcourt's silver blond hair and green eyes were given extra attention because of how striking they made her look. In Shadowhunters, she's dark-haired and dark-eyed.
In Un Burattino Di Nome Pinocchio, Geppetto's hair is blonde instead of greying. That was done to replace a yellow wig wore by Geppetto in the original book, which was used to mock Geppetto by calling him Polentina.
In La dame aux camélias (aka Camille), Marguerite has black hair, like her real-life inspiration Marie Duplessis. The famous 1936 film version stars the honey blonde/golden brown haired Greta Garbo, the 1984 TV version has the same-named and similar hair-colored Greta Scacchi, Violetta's hair color in the opera La Traviata depends on the soprano, and in Moulin Rouge! (not quite a straight Camille adaptation, but clearly inspired by it) Nicole Kidman's Satine is a redhead.
In Bridge to Terabithia, Leslie is described as a brunette girl with Boyish Short Hair. The 1985 adaptation keeps this, however the 2007 adaptation has her as a blonde with medium-length hair.
Hatchet's Brian Robeson is depicted as a brunette on the book cover, but the 1990 TV film, A Cry in the Wild, makes him a blonde.
Rabbit's fur was brown in the illustrations of the A.A. Milne novels, but the Disney adaptations gave him yellow fur (with the exception of The New Adventures of Winnie the Pooh, where he has light green fur).
Eeyore has dark grey fur and a light gray muzzle in the original novel, movies and shows, but in most modern promotional artwork and merchandise he is depicted with blue fur and a flesh-colored muzzle, possibly to make him more noticeable and appealing to young children.