Dress-Coded for Your Convenience

In The Matrix, a Badass Longcoat = Freedom Fighter, while Clean-Cut Hair and a Suit = Evil Tool of ~~The Man~~ The Computer.

"There's a reason armies wear uniforms even though they make them easy to spot. Sometimes that's what you want. Uniforms suggest organization, power and numbers. These in turn inspire fear. And as any good operative knows there is no more effective weapon than fear."

—Michael Westen, Burn Notice, "Hotspot"

Basically, when you can tell sides in a conflict by what they wear. It doesn't matter the specifics of what they wear, just that one side has a distinctly different dress than the other.

This is actually quite common in fiction. One example is wearing a uniform for any military, either in fiction or Real Life (since you need to tell who to stab/shoot at). This also means this trope can be enforced by an actual Dress Code.

Other times, it can be cultural dresses or the personal styles of the heroes and villains.

This can also apply even with Gray and Gray Morality. Just because you don't know which side is really the bad guys, doesn't mean you still can't tell one side from the other.

Distinctive Appearances is a Super-Trope. See also Alike and Antithetical Adversaries for how this can be illustrated in a conflict.

A Super-Trope to:

Compare Hollywood Dress Code, Color Coded for Your Convenience, Good Eyes, Evil Eyes, Obviously Evil, Highly-Conspicuous Uniform, Characteristic Clothing Colors, Slobs Versus Snobs.

Examples of Dress-Coded for Your Convenience include:

Anime and Manga

Sailor Moon: any Sailor Senshi. The bad guys have their particular style and the good guys have their short skirts and leotards.
- All Sailor Senshi in the UNIVERSE share some semblance to this, even if it's just a Sailor Collar and some form of Tiara. When the final arc introduces evil Sailor Senshi, it's still easy to tell them apart. Heroes: same as always or bikini top, hotpants, thigh high boots, elbow length gloves (Sailor Starlights), and the Villans have...everything else.
Claymore zigzags it: at first, it looks like the stylish, uniformed Claymores are the good guys protecting humanity from the amorphous, shapeshifting yoma. Then it turns out, they are Not So Different from yoma, after all. However, their real, much worse enemies are the Awakened Beings who don't wear special clothes, but each have a distinct appearance in their Awakened form (in contrast to Claymore uniforms whose only distinct feature is their symbols). Then, after the Time Skip, we get the Sexy Seven nicknamed so for their new sexy black uniforms. So now we've got the Good-But-Misguided uniformed Claymores working for The Man, the Good, rebellious, black-clad Sexy Seven, and the Ultra-Evil Awakened Beings, each with their distinct appearance.

Comic Books

In the Tintin story The Calculus Affair, a fight has broken out between the Syldavians, who all wear brown coats, and the Bordurians, who all wear grey coats and have shaved heads. Despite this, the Captain doesn't know which side to aim for, so Tintin just tells him to go for the ugliest mugs.
Rogue Trooper - the Norts wear rubbery suits and gas masks, while the Southers wear harder armour and clear visors.

Film

As in the picture, Agents in The Matrix dressed like government agents, while the good guys wore mostly black, stylish clothing.
In the original Star Wars trilogy, the rebels had a variety of uniforms, and so did The Empire. It's just the styles of them were easy to tell apart.
- The Sith and the Jedi. Hell, even before his Face Heel Turn, Anakin was wearing tons of black leather in sharp contrast to Obi-Wan's tan robes.
- Averted/inverted with Luke, who goes from wearing white to gray to black during his journey from farm boy to Jedi in parts IV through III.
In The Rocky Horror Picture Show, at first, Brad and Janet wear more conservative clothing compared to Frank N. Furter (who is in women's lingerie). Later in the film, when they are corrupted, they are stripped down to their underwear and also end up wearing the same clothing as Frank during the floorshow.
The Dark Knight: The Joker used this trope for his advantage. The doctors were the joker's men and the clowns were hostages.

Literature

In Steven Brust's Dragaera stories, all Dragaerans belong to one of 17 (or more) great Houses. Each House has its own colors and most Dragaerans typically wear some variant of those colors. Jhereg wear grey and black, Dragons wear black and silver, Phoenix wear gold (not yellow, gold), and Orca wear pale blue and green. The House of the Yendi is the only one which doesn't have set colors.
Wizards in Dragonlance, at least prior to the Second Cataclysm, had a strict dress code: Good wizards wore white robes, neutral wizards wore red robes, and evil wizards wore black robes. This troper seems to recall Raistlin's robe changing colour as his alignment shifted.
- Only in a dream. In the waking world, he actually had to go through the trouble of dyeing his robes. It's also mentioned that he broke the rules by not officially declaring his change of colour to the Conclave.
Terry Pratchett averts this trope on multiple occasions, most notably with Lady Margolotta from The Fifth Elephant. Fluffy pink cardigans are not standard vampire wear, not even when patterned with a bat motif.

Live-Action TV

Stargate Atlantis has each side wearing their respective military uniform, with a few off-worlders in native dress thrown in for variety. But flip the Matrix example for fun—it's the good guys who wear the regular military clothes and the Wraith who wear the leather.
- And going the other way, the expedition's baggy battledress contrasts nicely with the Genii and their habit of Putting on the Reich.
- In Stargate SG-1, it's pretty easy to tell Jaffa in full gear apart from everyone else. They were metallic armor that was mostly ineffectual against bullets and is mostly ceremonial. Different Goa'uld also have different styles of headdress for their Jaffa. Only two are shown on-screen: the falcon-headed guards of Ra's family (including Ra, Heru-ur, and Hathor) and the serpent-headed guards of Apophis (Ra's brother, by the way). The armor also makes a loud clang when marching, making them easy to spot from afar.
  - A third type of headdress worn by Setesh's (AKA Seth) Jaffa is mentioned in a joke but never shown, as Seth has long ago been exiled.
Babylon 5 takes a rather literal Planets of Hats approach to this. The Centauri dress like Prussian military, the Narn favour leather oddments dyed and visibly stitched together, the Minbari go for priestly robes, and later, we see the warrior caste use somewhat more functional clothing. The humans start in the same outfits, but then splinter and argue over the clothing bin. Even the spaceships of the various species follow this trope.
- Some EarthForce ships don't look very much alike. For example, the Hyperion-class heavy cruisers have a different design and different paint job than the Nova-class dreadnoughts and the Omega-class destroyers. This is due to them being produced by different defense contractors. The Hyperions were produced by KarmaTech and have a distinctly white (or light grey) and blue color scheme. The Rocketdyne-produced Novae and Omegas are entirely dark grey, or even black. Of course, this is likely further meant to show off how varied humans are compared to the other races. Then again, we don't get to see a lot of different types of ships from other races.
Played for laughs on That Mitchell and Webb Look where the Nazi officers start wondering if the skulls on their uniforms make them the bad guys.

Video Games

In Overblood, the good guys wear "jackets" that are too small for them. The bad guys don't.
Republic troops in Knights of the Old Republic wear orange, yellow, and black, while Sith troops wear chrome or metallic red.

Web Comics

The mercenaries, French soldiers, and rebels in Cry Havoc all wear different styles of gear. The mercs wear green or olive armor that is much larger and bulkier than the French's tan and brown vests. The rebels wear much brighter colors with light vests and armor or none at all.
Homestuck: This is a design feature of Sburb, in which natives and dreamers of Derse and Prospit dress according to their planet. Subverted in the kids' session, when the Black Queen liked harlequin colors enough to enforce it in uniform, and apparently so did the White Queen, as both Black and White armies dress similarly. The Kings still wear their own color.
- There are still differences in color between the two: the Prospitans usually going for light blues, yellows, greens, and pinks, while Dersians use darker versions of those colors with red instead of blue and purple instead of yellow.