Rustproof Blood

Look on the bright side: You'll find another in a few scenes.

Blood is always red. (Mammalian blood, anyway.) This is true even though blood fairly quickly curdles and scabs to a brownish color when exposed to air (because of the oxidation of the iron in the blood; hence the word "Rust" in the trope name), to the point that chocolate syrup is often recommended to fake scabs. Even literary description of the stains, if they are not shown, must specifically say that the stains are of blood in order to be understood. This is probably done as a bit of visual shorthand, to let the audience (and other characters) know that the stains in question are actually blood, as opposed to other things that stain brown, such as mud, chocolate or feces.

A similar error is to have fresh blood dilute when washed from red to a pinkish color. Due to the composition of blood (mostly red cells floating in plasma) diluting it with water actually turns it yellow, although it is feasible to have the water turn red if there’s a lot of blood going into not much water.

Contrast Black Blood, which is deliberately toned down to spare the audience the harshness of fresh red blood. Bloody Murder is, oddly enough, entirely unrelated.

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Examples:

Anime & Manga

• Angel Beats!, pictured. Otonashi's shirt is still sopping wet with bright red blood after he recovers from being stabbed in the chest in the clinic. Even with the Healing Factor, some of it ought to have dried. Or, you know, reabsorbed into his body, since that happens at a different point soon after.
• Averted in Appleseed: There' a rusty patch on the floor in an abandoned science lab. It isn't until a 3D security video is replayed that you realize it's dried blood.
• Dragon Ball: Bardock's headband, which was originally a white armband worn by one of his friends and was dyed completely red with blood after that friend's death, retains its vibrant shade of red during Bardock's final battle in The Father of Goku, and throughout the events of the sequel/prequel Episode of Bardock.
• Tengen Toppa Gurren Lagann: Kamina's red cape is not decorated with fire. It was an orange cape, and became red from his father's blood, who was murdered by Beastmen years before the series started.

Comic Books

• Averted in Johnny the Homicidal Maniac:
  "Blood changes color when it dries! Don't you see? I have to keep the wall wet!"

Films — Live-Action

• Despite only having had a single bucket of blood dumped on her, the titular character of Carrie remained red and dripping as she walked all the way home. Then, due to the type of fake blood used, when she washed it off in the bathtub it inexplicably turned pink. And despite sitting around for hours, the blood hadn't coagulated or turned brown in the bucket before being dumped on Carrie's head. In the novel, it had been transported in buckets of ice, and had frozen in transit, to thaw between placement and deployment.
• In The Brothers Bloom, the visual difference between dried real blood and stage blood clues a character that they're being conned.
• During the opening sequence of the movie version of Stephen Sondheim's Sweeney Todd: The Demon Barber of Fleet Street a large amount of blood goes through several gears, into a sewer, and eventually washes out to sea — it froths and coagulates a little, but stays a dark pink/pale red the entire time.
• In the Agatha Christie book and movie Death on the Nile, Poirot finds the murder weapon (which has been chucked into the titular river) wrapped inside a cloth. The mysterious pink stain on the cloth leads Poirot to suspect that one of the passengers faked a bloody injury (using red nail polish) in order to create an alibi for himself.
• The blood on Coulson's vintage Captain America cards in The Avengers... which turns out to be the first clue that Fury didn't find them where he said he did. They were in Coulson's locker when Loki stabbed him. Whether that means Fury just added the fake blood for extra punch or something else has yet to be seen.
• Deadpool's original white uniform is still bright red from the blood stains at the laundromat, long after the blood had time to dry up. (It could be considered Fridge Brilliance once you realize that his cells are immortal and never die.)
• Ripper: Letter from Hell: The killer writes a message on the wall in Marissa's blood at the scene of her murder. When Molly visits the crime scene a day later, the letters are still bright red.
• Twice-Told Tales: In "The House of Seven Gables", a chair in the study still bears a bright red bloodstain from the first of the male Pyncheon's to die in the house: 150 years earlier. Of course, his death was the result of a Curse which might have something to do with it.
• Knives Out: The spot of blood on Marta's shoe remains visibly red for several days after Harlan's death, even though it should have turned brown.

Folklore

• The redcap is a particularly vile goblin from British folklore that waylays you on the road at night, kills you, and soaks its hat in your blood; really it should be called the browncap. (Of course, it does go out of its way to get fresh "dye" every night...)
  • Ursula Vernon's "Little Creature and the Redcap" deals with a redcap's frustration with the nature of realistic blood.
  • Some versions of the myth say the redcap dies if the blood on its hat dries out or washes off. Which means it must have to re-dye its hat every hour or so.

Literature

• In the Merry Gentry series, certain Redcaps, usually the most powerful ones, have the magical ability to keep the blood on their hats from drying out and rusting.
• Death on the Nile has the bloodstained cloth wrapped around the gun. When they pull it out of the titular river, the water has diluted the bloodstain into a pink color. Then Subverted when Poirot correctly indicates that blood would not turn that color from the water — it's actually nail polish. The fact that it is not blood when the apparent sequence of events indicates that it should be is what puts him onto the killer's trail.

Live-Action TV

• CSI: NY: Mac Taylor's 333 Stalker sends him a 30 yr old bloody T-shirt. While it's not blood red, its certainly not rusty enough for its age.
• In Criminologist Himura and Mystery Writer Arisugawa, an idol's body shows up on stage covered in bright red blood, despite being murdered and put on ice days ago. The coroner's examination reveals that prop blood was mixed in to retain the red colour, which clues Himura in on how much emphasis the killer wanted to put on the body's display.
• On Desperate Housewives, a blood stain discovered under a carpet from a murder several months before is still red and able to be Hand Waved in-universe as being a wine stain.
• Dexter:
  • The pool of blood in which baby Dexter was found seems to have been made of this trope as it would have started to coagulate. Crime scenes he investigates as an adult also seem prone to this.
  • Justified with the blood in Marina View Hotel because it had been refrigerated and mixed with anticoagulants.
• In Game of Thrones, the day after the Red Wedding, the servants are scrubbing the blood off the floor, still red, still liquid.
• The suspicious redness of a bloodstain was a vital clue in an episode of Jonathan Creek.

• Lampshaded in an episode of Millennium (1996). Two people working on a slasher movie were fooling around with bags of fake blood shortly before they were murdered. This caused the crime to appear much more violent than it actually was. As Frank Black arrives at the scene he soon tastes some of the blood (to the puzzlement and revulsion of others present) and comments that it is fake blood, which he already figured out since real blood turns brown as it dries.
• Lampshaded in the "Tuesday the 17th" episode of Psych. While searching for a camp counselor who's been missing for days, Shawn, Gus, and the other counselors find her bloodstained pajamas in the laundry room. Later, Shawn comments that real blood would have dried and started flaking off by that point, which clues him in to the fact that it's all a hoax; the counselors are beta-testing a murder mystery/horror weekend they intend to hold at the camp.
• Averted in Smallville: Chloe's Blood-Splattered Wedding Dress turns black in the next episode.
• In the "Hook Man" (S01, Ep07) episode of Supernatural, bright red blood announces "AREN'T YOU GLAD YOU DIDN'T TURN ON THE LIGHT?" on the wall of Lori and Taylor's dorm room.
• In Unsere Mütter, unsere Väter SS-Sturmbannführer Hiemer's face is splattered with blood when he shoots a Jewish child in the head, and several scenes later he still has bright red stains on his neck.
• In De Vloek Van Manege Pegasus, the message supposedly written on the wall in blood remains bright red for days. It is later revealed to actually be red paint.
• The Wire falls into this trope, despite being otherwise brutally realistic. Not a drop of blood turns brown, despite the fact that the show frequently shows the murder, the investigation, and how much time has passed in between when the blood should have turned brown.

Pro Wrestling

• Obviously averted here, since unlike most performers, professional wrestlers are usually covered in real blood, often their own. CZW's Tournament of Death in particular is a great place to see the transition from red to rust in action, provided you're into that sort of thing.
• Played straight and averted with Su Yung. No matter how much time passes, her blood splattered gloves and wedding dresses will remain red or pink, both traits of this trope, but she's not above afraid of matches where someone will likely bleed rusting blood.

Tabletop Games

• Often appears in Warhammer 40,000.
  • For some factions (especially Khorne, the Blood God) it's presumably a magical gift.
  • In the case of the Eldar God Khaela Mensha Khaine, also known as the Bloody Handed God of Murder, the blood that drips eternally from his hands is that of the Eldar hero Eldanesh, whose murder began the War in Heaven and caused Khaine's curse to eternally have Eldanesh's blood on his hands.
  • Space Marine blood is both hyper-oxygenated and clots nearly instantly. Depending on the Writer this can lead to spilled blood staying crimson long after it's stopped flowing.
  • Games Workshop offers a paint named (appropriately enough) "Blood for the Blood God" which is a livid, glossy red for painting blood spatter and gore on your models. Since it's a gloss paint, the "blood" will always look fresh.
  • The World Eaters, Khorne's dedicated berserkers, have red-and-brass armor, which was blue-and-white pre-Heresy. Naturally, the idea is that they've done so much killing that their armor has been stained by the blood, but the Real Life aversion of this trope refutes it (In-Universe even).

Video Games

• In 99% of violent video games, old bloodstains might be, for example, reddish-brown at the darkest; and new blood will be red and stay red no matter how long the corpse lingers.
• In BioShock, not only are all the blood stains bright red — many of which must have been there at least a year — they're still wet and shiny!
• The Chzo Mythos games play this pretty straight most of the game. There's one notable exception in Trilby's Notes with one room that needs to be opened from the Dark World. When analyzing the brownish stains in the room, Trilby identifies them as dried blood and deduces the room must have been unoccupied for a long time.
• Dead Space 3 is perhaps the most heinous offender. The Sovereign Colonies Galactic Expedition wiped itself out 200 years prior to the events of the game... But there is plenty of splattered blood around the place that's just slightly darker in color, rather than completely bleached or at least brown. Gets downright ridiculous in the pressurized, properly oxygenated environment of the derelict starships in orbit around Tau Volantis. Possibly justified with a bit of Fridge Logic: Late in the game you find a leaper that's been pinned to a wall, and a note near by that tells you that, even after you shoot them to pieces, the cells in a necromorph don't die, seemingly kept "alive" by the Marker Signal. If it's necromorph blood (and after two hundred years, it would be) then it couldn't degrade.
• Averted in Doki Doki Literature Club!. After Yuri succumbs to her Mind Rape, she kills herself with a butcher knife. The Player Character is forced to sit there with her corpse for an entire weekend, during which time her blood turns from bright red to dark brown. In addition, her eyes go blank and her skin goes pale.
• In Dragon Age, blood never seems to dry. Maybe warriors clean their armor off frequently, but one would assume mages in cloth robes/light armour or rogues in light/medium leather armor would have some trouble getting all the stains off. Also, you just keep getting hosed off with more blood in every single fight. They just need to get enough off so all that's left will just blend in with everything else in the game.
• Uncharted: Drake's Fortune averts this trope properly; Drake comes across a beached U-Boat, whose crew were really torn up by something. Over the decades, all the blood on the surfaces and corpses has faded to a rusty brown that's not even recognizable as blood unless you know what to look for.
• Averted in some instances in Fallout 3. The town of Minefield is full of decayed corpses. However, as the player searchs for mines they might spot a trail of bright red blood leading to a house, with a bloody red palm print on the door. The fact that this blood is fresh is a clue that the player is about to be attacked by a sniper. Played completely straight in abandoned areas, such as Vault 87.
• Exaggerated/ Parodied in Super Meat Boy. The titular Meat Boy bleeds everywhere, leaving a bright red trail everywhere he runs and jumps. And yes, when you are inevitably shredded by the many, many buzzsaws, they stain red too. If you fall onto them repeatedly, they become bloodier and bloodier with each death.
• Silent Hill plays with this trope, where sometimes you must question if the walls are covered in rust or dried blood... as well as the fact that some monsters bleed blood that looks almost brown. There's plenty of fresh-looking blood to be found decorating the town's hellish Dark World, but given the nature of things it's hard to say how long it's supposed to have been there, or if it was ever even spilled from a living creature to begin with.
• Example from The Legend of Zelda: Ocarina of Time. The bloodstains on the Shadow Temple's torture equipment look bright and fresh — although this could just be an apparition, what with it being inside a magic temple and all... Or, to up the ante on the Nightmare Fuel quotient of that place, it really could have been fresh... The 3DS remake makes them more brown, though.
• True of every bloodstain ever appearing in the Ace Attorney series. Or if not all, then at least most. This at one point causes problems for one character, who can't distinguish red on white.
  • Though a subversion does appear in Spirit of Justice; in Turnabout Revolution, a corpse that's several days old is found in the middle of the trial. There's no time for proper testing, but one blood splatter near the arm is bright red, while the blood around the fatal chest wounds is dark brown. This is a major clue for the player, since it indicates the corpse's clothes were borrowed and used in a more recent murder, which is where the fresh blood came from.
• Averted in Professor Layton vs. Phoenix Wright: Ace Attorney, when a stain on a piece of evidence is called "blackish" (and indeed is just very dark) and Phoenix only realizes it's blood when the witness states she scratched her attacker's flesh when fighting with the item in question.
• Danganronpa: Trigger Happy Havoc has a variation; while all fresh blood is colored bright pink, though characters still describe it as red, the few instances of dried blood, such as Classroom 5-C and the second floor of the dorms are colored dark red. The same applies to the blood on Junk Monokumas in the Spin-Off Danganronpa Another Episode: Ultra Despair Girls.
• SCP: Secret Laboratory averted this with the Parabellum update - bloodstains will darken over time, going from a bright red to a brown colour. Before this, their colour remained static.

Web Comics

• The protagonist of SwordCat Princess wears what appears to be bright red war paint while in costume as her superhero alter ego, Artemis. This "paint" is actually the blood of her dead lover, Étienne, who died in 1014 AD.

Web Original

• In Death by Cliché, a villain's carpet is described as "brown, not because it was a tasteful colour, but because eventually blood dried."
• Inverted in the Fewdio short horror piece, "Cleansed". The thicker pools of blood turn dark and sticky while the lighter stains darkened to brown.
• In Madgie, what did you do? XLVII: Myxoma, Madness, and The Beginning of World War III, Toki stains her white slip in blood (twice) and it still remains bloodstained throughout the rest of the story and she still remained covered in blood, apparently, while it had dried, it didn't seem have decomposed.

Real Life

• Reality Is Unrealistic: The Heeresgeschichtliches Museum (Army History Museum) in Vienna houses in a display case the uniform that Archduke Franz Ferdinand was wearing when he was assassinated in Sarajevo in 1914. Complete with bloodstains, which have bleached white over the years. This is because of the light, as the color red fades over the years due to exposure to sunlight.
• Bloodstains are often so similar to rust stains that it's impossible to distinguish them unless a proper chemical analysis is done. There were a lot of cases when they were confused for each other, including one during the original Mary Celeste trial. The prosecutor insisted that the brownish stains on a saber, found on a ship, were blood, until the judge ordered them to be analyzed, where they were proved to be just rust.

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