“Good” characters typically wear red, blue, and yellow.
Pink is just light red, which we read as feminine. If heroes wear red, heroines wear pink.
By contrast, dark red—or any instance of red and black together—signifies evil.
Purple and green are also “evil,” especially together.
At TV Tropes puts it, the rule is “primary-color champion” and “secondary-color nemesis.”
But wait… There’s more
Obviously, heroes can also wear purple, green, and black.
And villains can wear pink, red, blue, and yellow.
When analyzing color in costumes, it’s not enough to say primary good or dark bad or what have you.
Although these tropes are part of the Western canon…
(The Virgin in blue; the devil in dark red…)
Cultural conditioning alone doesn’t explain how colors convey the intended effect.
To understand color in costume, we must look at color harmony: how colors in hair, makeup, clothing, lighting, and backgrounds harmonize with a character’s skin.
Color harmony is power
Powerful characters—good and evil—wear colors that harmonize with their skin. Weak characters wear colors that clash with their skin.
Consider Emily in The Devil Wears Prada. She victimizes the film’s heroine, but she herself is weak: a fashion victim.
Costume designer Patricia Field chose warm, dark colors because they make Emily look unnatural, vain, and ill. But why?
- Non-harmonious colors are overpowering. All we see is dyed red hair, purple eyeshadow, and moody red-brown outfits. Emily doesn’t wear her clothes; they wear her.
- Non-harmonious colors stand out. Emily’s eyeshadow draws our attention, so that we notice her heavy makeup and assume she is image-obsessed.
- Non-harmonious colors distort skin color. Emily’s skin appears both whiter and redder next to her red-brown hair and clothes.
Actor Emily Blunt’s best colors are blue-based and medium-deep. In a different film, dressed in blue to play the ballerina love interest, we see her.
Since the makeup colors appear to emanate from her skin, rather than sit on top of it, her makeup is less noticeable.
She might be wearing just as much eyeshadow, but because it’s in colors that suit her skin, the effect is “natural”—and so she appears virtuous, not vain.
Powerful villains are harmonious in “evil” colors
The “evil” character who truly wields power in Prada is Miranda, the boss.
She gets purple, the color of royalty, in a cool tone that goes beautifully with her silver hair and skin. Her cheeks are rosy, her eyes clear; she appears healthy, alive, and in charge.
Still, you can’t get too comfortable in her presence. Note the bright green ring, black chair, and ruby earrings—purple and green, black and dark red—there’s a hint of evil here.
When the villain is meant to be obvious, the character might need to have grey, green, or purple skin to harmonize with the evil color palette.
Since these are not natural human skin colors, a live-action villain’s skin may be artificially harmonized through lighting and makeup.
In such cases, the costume appears evil because it goes with unnatural skin.
Colors are “evil” because they make characters look evil
I know this sounds circular, but bear with me.
Clearly, evil colors indicate evil characters.
Even in books, certain colors belong to untrustworthy characters, as with Rita Skeeter’s signature acid green in Harry Potter and the Goblet of Fire.
“You won’t mind, Harry, if I use a Quick-Quotes Quill? It leaves me free to talk to you normally…”
“A what?” said Harry.
Rita Skeeter’s smile widened. Harry counted three gold teeth. She reached again into her crocodile bag, and drew out a long acid-green quill and a roll of parchment […].”
But why is acid green evil? TV Tropes theorizes that evil green is bright yellow-green because it’s dangerous and unnatural, like radioactive chemicals, whereas good green is more of a blue-green—forest green—because it represents nature.
But this overlooks a crucial point. There is nothing inherently natural about a given color. Whether it appears that way has nothing to do with the color itself, and everything to do with how it looks on the character.
In books, we can read the word “acid” and know the color is unnatural-looking. But on screen, whether a color appears “acid green” depends on who’s wearing it.
So how did the Harry Potter filmmakers ensure the same effect came through on screen? By casting an actor, Miranda Richardson, who could not possibly look natural in yellow-green.
Sure, she looks alive, but that’s only because of her lightened hair and over-bright makeup. The effect is perky, irritating, and artificial, just as her character is meant to be.
Richardson wears yellow-green again in The Young Victoria. This time, with different lighting and softer hair and makeup, she looks tired and sallow.
She’s playing a villain again—obviously. You can tell just by looking at her.
But this isn’t because yellow-green is inherently unnatural, acidic, or evil-looking. It just looks that way on her.
If the costume color looked natural against the character’s healthy human skin, she would look radiant—and we would assume she was good, not evil.
For example, bright yellow-green is luminous on actor Gugu Mbatha-Raw.
She’d have to wear something else to play a villain, because acid green makes her a goddess. Wouldn’t she be perfect in a live-action Princess and the Frog?
Notice that Tiana appears in a forest, where her outfit glows naturally like the fireflies around her (not “unnaturally” like toxic chemicals). A color that might look acidic elsewhere is magical here.
To summarize: There’s nothing inherently unnatural or acidic about yellow-green. It only looks that way when it clashes with the character’s skin.
More broadly, there’s nothing inherently evil about any color. Colors only appear evil when they make a character’s skin look unnatural.
Color and character development
Changes in clothing color can emphasize character development. Consider Gone With the Wind, in which costume designer Walter Plunkett uses two subtly different shades of green to brilliant effect.
Near the start of the film, Scarlett appears innocent in a woodsy shade of green.
Later, as she becomes more desperate to save herself through any selfish means necessary, the green takes on a yellow tinge that appears slightly putrid next to her skin.
On Vivien Leigh, this has the intended effect. Whereas on someone who looks great in yellow-green—like Gugu Mbatha-Raw, or Zhang Ziyi—the same color change would appear to show her character gaining integrity.
When a costume color harmonizes with a character’s unnatural skin color—or adds a sickly cast to otherwise normal skin—it signifies evil.
- Harmony with healthy skin signifies beauty, health, strength, and possibly goodness. (Like Princess Tiana.)
- Harmony with unnatural skin signifies power, evil, and the sinister supernatural. (Like Maleficent.)
- Disharmony with skin signifies weakness, sickness, and ill/evil intent. (Like Emily in The Devil Wears Prada.)
You can wear whatever color you like, but knowing your best colors lets you dress like the hero of your own life.
 Other costume-color tropes include…
- Blue: Blue Is Heroic; Heavenly Blue.
- Red/Pink: Red Is Heroic; Pink Heroine.
- Yellow/Gold: Hair of Gold, Heart of Gold.
- Black: Dark Is Not Evil.
- White: Light Is Good; Gold and White Are Divine.
- Red: Red and Black and Evil All Over; Red Is Violent; White and Red and Eerie All Over.
- Green: Green and Mean; Sickly Green Glow.
- Gray: Grayscale of Evil.
- Black: Evil Wears Black; Dark Is Evil.
- White: Light Is Not Good; Villain in a White Suit.
Source: “Good Colors, Evil Colors,” TVtropes.org/pmwiki/pmwiki.php/Main/GoodColorsEvilColors.
 Disclaimer: Of course, even in impeccably costumed films, characters sometimes wear colors that aren’t their best.
Costume designers may not be aware of all aspects of color harmony. For instance, perhaps they can tell that an actor looks good in blue and green, but they haven’t realized that she only looks good in cool colors. So you end up with Emily Blunt in a beautiful blue-green dress, but with the effect somewhat tarnished by gold jewelry and decor.
On the other hand, maybe the discordant effect is intentional. Perhaps costume designer Sandy Powell wants Victoria to look ill at ease in the palace, but relaxed outdoors.
Anyway, not every costume choice has a reason. As writer Flannery O’Connor said when asked about the significance of her character, the Misfit’s, hat: “The significance of the Misfit’s hat is to cover the Misfit’s head.”
“Good characters may wield power that has a green glow, but this is always a ‘healthy’ or ‘natural’ shade of green. Evil green is a more sickly, yellower shade that makes you want to take a shower to wash it off after just looking at it.”
See the trope “Sickly Green Glow,” TVtropes.org/pmwiki/pmwiki.php/Main/SicklyGreenGlow.
 Okay, the mascara is too black and the lipstick is too bright and warm. Aside from that, she looks sensational. Scroll back up to her in Harry Potter and The Young Victoria—does that even look like the same person?!