Writing Indentation Clue

It is a pity he did not write it in pencil: as you have no doubt frequently observed, Watson, the impression usually goes through — a fact which has dissolved many a happy marriage.

— The Adventure of the Missing Three-Quarter

When people write a letter or a note, it's possible that the pressure of their pen or pencil will create indentations not just on the paper they're writing on, but on any paper that's underneath it, too. In some sorts of story (particularly Mystery Fiction, though not exclusively), making use of this fact is a well-established investigative technique. If you want to know what someone wrote on a notepad but the note is no longer there, just look at the next piece, possibly shading it with a pencil to bring out the contrast.

In certain genres and at certain times, this trope has been common enough that a savvy villain might take steps to avoid it, such as by taking several sheets from a notepad or slipping a piece of cardboard between the top two sheets, to prevent the pesky detective from doing this.

A number of variations on this exist — for example, it isn't always paper that the indentation gets made on. A similar concept from the time when writing involved a lot of wet ink was to look at the blotting paper (used to absorb excess ink). Carbon-copy and triplicate-copy paper are designed to take advantage of this, allowing the impression to release ink so that multiple copies are written or typed at once.

Subtrope of Invisible Writing, and sister trope to Condensation Clue.

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Examples:

Anime & Manga

• Case Closed uses this method to gather clues occasionally.
• In Death Note it becomes vitally important in the final story arc. Light has had the Death Note for so long, using it to become the mass-murderer (and in his mind, Living God) "Kira" (Killer), and been able to successfully dupe for so long the police team that he's a member of which is meant to hunt Kira, that he gets, well...overconfident and sloppy. He has meetings with one of his new catspaws, which he realizes are being recorded by hidden microphones, so he has seemingly normal conversations with her in their hotel room, while passing her hand-written notes giving his real Kira-directed instructions. Unfortunately for him, his police colleagues finally grow suspicious of him - well, he was always one of the top suspects to be Kira, but he managed to trick them with so many fake alibis that they had long since written him off as a red herring. At any rate, one of them later goes into the hotel room he was in and uses the writing indentation clue on the notepad he was writing instructions to his agent on — Light grew so overconfident that he stupidly forgot about this little trick entirely. While the actual content of the indentations wasn't particularly damning, the fact that he was trading secret messages instantly tipped them off that he'd been throwing up smokescreen misdirections, a red flag that he actually was Kira.
  • Was this something that happened in one of the movies? Because I don't remember that being the way it went down at all. In the anime Aizawa suspected Light was writing notes, and made his own indentations on the bottom of the notepads to see if they'd still be there when he checked out the room after Light left. Since they disappeared it confirmed his suspicions that Light was actually Kira. It ultimately comes to nothing. Light suspected Aizawa was up to something but was unconcerned, and, just as Light thought, Near showed no interest either because Aizawa couldn't produce the contents of the note pads which could have damning evidence.

Comic Books

• A circa '70s Archie story had Big Moose going missing just before a big baseball game with Central High. Archie and Jughead trace Moose's recent whereabouts to a telegram office where Moose received a handwritten note. Archie used the indentation clue method to find out Moose was at the bus station waiting to go to the city where a family matter called him. It turns out that it was a Central High trick to get Moose out of the game. Archie and Jughead transport an incensed Moose back to Riverdale where he cleans up Central High virtually single-handed.
• This is the way a blind man solves a mystery in the Vampirella magazine story "Blind Justice". No-one else noticed it, but he points out he couldn't "overlook" it since he is trained with Braille.

Fan Works

• In the Law & Order: UK story "Dreadlock Holiday", Matt disappears after being humiliated in court. Ronnie and Alesha go to his apartments to look for clues about where he's gone and Alesha uses the shading technique on a notepad she finds to read "Take cat to Niamh's" (his sister)

Films — Live-Action

• Animal House has the Deltas trying to steal the mimeograph stencil (look it up, youngsters!) of a mid-term exam, so they can do well in the class without having to actually study the material. Unfortunately, the Omegas had already stolen the actual stencil and substituted a fake stencil with all of the answers being wrong.
• Subverted in The Big Lebowski: The Dude uses this trick to see what the pornographer Jackie Treehorn wrote while taking a phone call, but it turns out to be just a doodle of a man with a Gag Penis.
• Used in Cloud Atlas to figure out the address of a murdered scientist's daughter.
• The Fourth Protocol is about a Soviet plot to detonate a nuclear device on British soil and Make It Look Like an Accident. As such an act violates a secret protocol between the nuclear powers, various people get bumped off because They Know Too Much. A female military scientist is sent to assemble the bomb that the KGB agent played by Pierce Brosnan will detonate. She delivers a message which Brosnan decodes using a one-time pad, then he burns the message claiming that it just confirms her instructions (re: setting off the bomb). She ends up sleeping with him, and the morning after rolls over in bed and sees the imprint on the notepad: KILL HER. Brosnan immediately shoves a pillow against her chest and fires his gun through it.
• In the Mexican film La Habitacion Azul, this is how the cop of the movie discovers a message Andrea sent to her lover after her husband died, saying "Now it's your turn"; he uses it to accuse Andrea of murdering her husband and egging her lover on doing the same with his wife.
• In M the child-murderer writes a letter to the newspaper, using a single sheet of paper, a pencil and a wide windowsill in his apartment as a desk. When the police raid the apartment, they find a partial impression of the words in the letter in the wood. In this case, they already knew what had been written; the indentations were, instead, proof of who had written it.
• In North By Northwest, Thornhill is able to figure out where Eve is going by finding the impression of an address she wrote.
• In Paddington 2, Mary sneaks into Phoenix's apartment and uses this trick to obtain the location of the MacGuffin which he wrote down on a notepad earlier.
• The Russia House. The protagonist is taught to write on a glass surface to avoid this trope. He later does so, using a picture taken off the wall.
• Strings shakes it up a little, when its inadvertent usage implicates Nezo.
• In Tusk, detective Guy Lapointe uses this method to reveal an address Wallace had written down on a note pad before his subsequent disappearance. Teddy notes that he recognizes the trick from The Big Lebowski, and Lapointe admits that's where he learned it.
• Wild Wild West. Dr. Loveless writes down information about the rendezvous point on a piece of paper and gives it to Bloodbath McGrath. Jim West uses this technique to discover where the rendezvous point will be.

Literature

• The Berenstain Bears: Used in the Big Chapter Book The Berenstain Bears and the Bermuda Triangle, revealing that Bermuda had copied down what appears to be a phone number. It's actually the number to the in-school modem, letting someone log into the school's private network and steal information from his teacher's files.
• In Bulldog Drummond, a mook assigned to trail Drummond uses this to find out what Drummond wrote in a telegram—but reveals a rude message from Drummond, who'd realised he was being followed.
• In The Death of Achilles, Fandorin figures out the bad guy's address by tracing the indentation in a notepad he found on the scene.
• The Dresden Files: In Death Masks, Harry Dresden recovers a thief's notepad after seeing her tear off the top page. He shades the page underneath it with charcoal to find out what she'd written.
• The psychokinetic children in From the New World are given their own mantra and told to keep it a secret, but the heroine was curious enough to persuade her classmate into writing down his mantra and giving her a glimpse of it. She couldn't see it clearly, of course, but she read it by shading the sheet underneath with a pencil after he left.
• In the novelization of Gabriel Knight: Sins of the Fathers, when Gabriel discovers that Professor Hartridge is dead, he also finds that the office has been picked clean of evidence, including some notes the professor had been working on to help Gabriel. Fortunately, there's enough indentation left in the sheets underneath the removed notes that Gabriel is able to use a pencil to employ this trope to find out what the professor had written anyway. (In the game itself, Gabriel is able to just take the notes without having to go through all that.)
• A variant is used in Half Moon Investigations: when his sister Hazel brings him a note from her boyfriend that doesn't sound right, Fletcher notices several pieces of evidence that point to the note being erased and rewritten several times on the same sheet of paper. He takes a pile of graphite shavings, spreads them across the paper, and slowly shakes them off. Some of the shavings get caught in the dents from the erased notes, allowing them to be read. Hazel's boyfriend is in an affair and started writing a break-up note before erasing it and trying something gentler.
• Played with in Jingo, part of the City Watch subseries of the Discworld books. Someone had written a note on a pad of paper, but someone else came along and took the next few pages to prevent anyone else using this technique. Vimes addresses the resultant Fridge Logic: Why didn't he just take the whole pad? Because he also wanted Vimes to be curious about the contents of the note.
• In Les Misérables, Valjean discovers Cosette's letters to Marius by looking at the blotting paper.
• The Miss Marple short story "The Tuesday Night Club" from The Thirteen Problems: Very shortly before his well-off wife dies, a man writes a letter; the rather suspicious phrases "hundreds and thousands" and "when she is dead" are picked up from the blotting-paper. The man, however, explains that he was writing a reply to his brother, who had asked for money; whilst he would have money after his wife was dead, he had none currently, and that hundreds and thousands of people were in the same boat. He's lying.
• In the historical detective novel The Silver Pigs, Marcus Didius Falco finds a denunciation of a political conspiracy written out on a wax tablet. However one of the names has been crossed out, so Falco tries to work out the name from the scratches left by the writer's stylus on the wood beneath the wax.
• Referenced in one of the Mc Gurk Mysteries Series while also being given a minor deconstruction. The narrator of the books finds a clue to a mystery via this method but team scientist Brains calls him out on it, saying that this method unintentionally wipes potential clues.
• In The Secrets of Drearcliff Grange School, Amy deliberately creates a hidden message this way, writing an innocuous description of the Moth Club's insect-observing goals in the back of a book and then jotting its true, secret mission (rescuing Kali) in between the lines of the innocuous one with a pencil. She then erases the real goal's lines, leaving visible only the cover story that claims the girls' new secret society actually is about moths.
• Mentioned by Sherlock Holmes when telling Watson how he got his information as "a fact that has dissolved many a happy marriage". However, in this case, he uses the blotting paper to obtain the reverse message, as the writer had used a pen.
• Sherlock Holmes and Doctor Was Not: In "The Sign of Two", Holmes rubs a pencil over the top sheet of Dr. Jekyll's notebook and is able to bring up some of his notes: enough to give him an indication of what he is working on.
• This is the key to Steve Berry's The Third Secret, based on the visions of Our Lady of Fatima. In reality, three children saw the Virgin Mary and heard her confide three secrets. Two were revealed later, with the third secret not to be opened until after 1960. It was read by Pope John XXIII and by subsequent popes, but wasn't made public until 2000. In the novel, John can't read Lucia's old-fashioned Portuguese, so he gets a translator to write it in modern Portuguese and in Italian. The translator has a very heavy hand and his writing is impressed on the page below; moved by an interior impulse, he later shades out the impressions and keeps them. This is the "facsimile" that he later sends to Pope Clement VIII, and this is where the story really starts.
• Mentioned briefly in the book version of The Time Traveler's Wife; this is how Clare discovers Henry's intention to get a vasectomy.

Live-Action TV

• In Angel, when Cordelia's missing, Angel suggests trying this with her memo pad to see what the last message she wrote down was. Gunn counter-suggests checking the carbon copy.
• In an episode of Ashes to Ashes (2008), Alex Drake uses a pencil on Super Mac's Diary to uncover a secret meeting between him and a murder suspect.
• A variation in Batwoman (2019). The title character is knocked down by a truck driven by the Villain of the Week. Fortunately the Batsuit records deformation impact data—as from bullets or blunt force trauma—which software can then analyze to reveal patterns, so part of the license number is recorded this way.
• Blake's 7. In "Killer", Avon and Vila blackmail a technician into helping them commit sabotage; however, he writes out a message (because Avon and Vila are listening in the next room) and hands it to an underling to be transmitted to Star Command, warning them of the rebels' presence. Later the technician crushes up the remains of a thermal bomb to avoid leaving evidence behind. As Vila is sweeping up the soot, he notices the pad used earlier and covers it with the soot to read the message.
• An episode of Bones has them use a high tech version of this to recover the writing from a blood-soaked notebook.
• Columbo:
  • In the episode "Now You See Him", the Great Santini shoots Jesse Jerome immediately after Jerome types a letter exposing Santini as a wanted war criminal named Sgt. Stefan Mueller. Columbo catches Santini by examining the typewriter ribbon, which contained an impression of all the keys the victim had pressed.
  • In "Columbo Likes the Nightlife" Justin Prince removes a page from Linwood Cobin's calendar to remove evidence of Cobin's extortion scheme, but this just raises Columbo's suspicions since it's strange someone would remove a calendar page before a "suicide". As it turns out, the indentation is still there.
• CSI: NY:
  • In "All in the Family," Flack goes to Danny's apartment looking for him since he didn't show up to work. He notices indentations on a program from Ruben Sandoval's memorial service and uses a pencil to shade that section and figures out where Danny went.
  • "Late Admissions" has the motive revealed by shading an entire page in the Body of the Week's notebook. The victim, a high school junior, had discovered a dextroamphetamine abuse epidemic in his elite preparatory academy and was going to blow the whistle on it by writing a letter to the editor of The New York Times.
• The Doctor Blake Mysteries: In "First Dance", Lucien finds the last page of the Victim of the Week's algebra exercise book has been pulled out. Lucien rubs a pencil over the sheet underneath to find the impression of a blackmail note she had been composing.
• Anytime Dr. Quinn, Medicine Woman has needed to invoke Loophole Abuse to get the local telegraph operator to tell her about a message that he sent (he's taken an oath to keep such communications private), she'll usually take the notepad that he wrote the message on and shade it to find out what was transmitted.
• In Elementary, a piece of newspaper is found at a bombing that killed two people. A word was found indented on one of the pieces of newspaper used to make it and the handwriting on it was matched to the bomber.
• In the Eureka episode "Before I Forget", Carter starts to write a ticket for the villain of the week, only to be given Laser-Guided Amnesia and have the ticket stolen. Later he works out this happened and uses this technique to recover a partial license plate. Amusingly, Henry starts to talk about a high-tech method he can use to recover it, only to trail off as Carter does it.
• Father Brown: In "The Devil You Know", Father Brown rubs a pencil over the notebook of the Victim of the Week to bring up most of a note he had written and then torn out and sent to the War Office.
• In an episode of Friday Night Lights, Buddy has been kicked out of his house by his wife because of infidelity. When he shows up at Coach Taylor's home in the middle of the night, they feel pressured into taking him in. He then precedes to become the guest from hell, monopolizing the tv and the bathroom, and using this trope method to find out that Coach Taylor was being courted for another, better-paying coaching job, which Buddy then begins to harangue the coach for even considering.
• One episode of Honey, I Shrunk the Kids had Wayne and his estranged brother Randy Rude, the Science Dude (A Bill Nye Expy), accidentally shrunken and wind up getting into some kid's McDonald's Happy Meal. The kid's mother had filled out a card for a contest that the restaurant was holding, so Mrs. Szalinski and the restaurant staff were able to get the address off the next card on the pad by adding lemon juice and heating the card.
• In an episode of Lois & Clark, Clark uses his powers to read several messages indented on a wooden desk.
• In the Discovery Channel's miniseries Manhunt: Unabomber (about the search for the Unabomber) has a Red Herring with this. One of the early leads is that the words "Call Nathan R." were indented on a document sent from the Unabomber. It turns out that one of the first people handling evidence wrote a Post-It note on top of the letter, so the indentation was not from the bomber.
• Midsomer Murders: In "Death in a Chocolate Box", Barnaby rubs a pencil over the notebook in the Victim of the Week's office to discover the last thing he wrote was a letter. Although Barnaby only gets the last part of the note, it is enough to tell him the letter exists and may have been the reason why he was murdered.
• Monk: In "Mr. Monk Takes His Medicine," the eponymous detective suspects that something is wrong with suicide victim Marlene Highsmith's suicide note. At first, he doesn't seem to know or care what is wrong because he is on Dioxynl, but when Monk goes off the drug, he realizes that the note was not Marlene's because it was written with a red pen, and there is no red pen in the kitchenette the note was written in. Monk takes the writing tablet the note was written on and uses chalk rubbing to reveal Marlene's actual suicide note - a confession that her ex-husband Lester Highsmith is staging an armored car robbery, that happens to be going down right at the moment Monk and Sharona discover the note. Lester had written the suicide note the police found and staged a drive-by shooting a few blocks away to keep the cops away while he switched out notes.
• Murder, She Wrote: Jessica does this in "Bloodlines" to reveal what the Victim of the Week had written down on the pad by the phone just before he was murdered.
• Murdoch Mysteries:
  • In the episode "Buffalo Shuffle", Murdoch uses graphite shavings from a pencil sharpener to raise some letters from a sheet in a notebook. He only finds some characters, so the meaning of the clue isn't readily apparent.
  • In the episode "High Voltage", Murdoch asks a hotel desk clerk about the occupant of a hotel room, and the clerk finds the relevant page from the hotel register is missing. Murdoch uses this method and a camera to recover a signature from the register's next page.
  • Chief Constable Davis uses this in "Bloody Hell", not realizing Murdoch was setting him up.
• My Life Is Murder: In "Sleep No More", Alexa uses a crayon to bring out the indentation on the top sheet of pad. While the sheet reveals what appears to be a confession, the fact that is on the top sheet means that it could not have been written weeks ago on the night of the murder as claimed.
• NCIS: McGee is a writer who still uses an old-fashioned typewriter. A Loony Fan steals his used typewriter ribbons and commits murders inspired by the plot.
• Found in an episode of Shark with two variations: the first being that it's not a text, but a drawing, the second that the detectives don't use a pencil to bring it out, but a computer.
• In the season six premiere of White Collar, Neal uses indentations and carbon paper to tip off Peter of to the fact that he's targeting the crime syndicate Pink Panthers, while his kidnapper and captor looks on and even checks to make sure Neal isn't passing messages.

Theater

• An Exaggerated Trope in Bullshot Crummond, when a mysterious assassin steals an important letter, but because the letter had tea spilled on it, its ink stained a cloth napkin so that Crummond can still figure out what it said.

Video Games

• It took nine games including all spin-off games, but this trope finally appears in the Ace Attorney series, in Spirit of Justice's DLC case. For extra irony, it's a diary with a torn-out page; exactly the same situation in Apollo Justice which got Phoenix disbarred because he got tricked into presenting forged evidence, specifically a forged version of Magnifi's last will and testament written in a torn-out page of his diary. In this case, he uses fingerprint powder to reveal the missing text.
• This is used in the second chapter of Another Code to reveal a note that Ashley's father wrote down.
• In Danganronpa: Trigger Happy Havoc, this is used in solving the first case, as there was a note passed between the culprit and victim that reveals that the victim called the culprit to "her" room (actually the main character's, because they'd swapped rooms) intending to kill him, only to wind up being the one killed when her would-be victim defended himself. One of the students even recognizes this trick from TV.
• Deadly Premonition: York uses this to find the contents of Becky's secret diary.
• In the remake of Gabriel Knight: Sins of the Fathers, when Gabriel discovers that Professor Hartridge is dead, he also finds that the office has been picked clean of evidence, including some notes the professor had been working on to help Gabriel. Fortunately, there's enough indentation left in the sheets underneath the removed notes that Gabriel is able to use a pencil to employ this trope to find out what the professor had written anyway. In the original game, Gabriel is able to just take the notes without having to go through all that.
• Cole uses this trick to gather evidence for a few cases in L.A. Noire.
• Used in Scratches, when Michael reveals a letter from the former maid of the mansion to her family, in which she details her account on the events that happened in the mansion and revealing the location of a secret compartment.
• In Season of Mystery: The Cherry Blossom Murders, this provides evidence of what (and who) the protagonist's husband had been looking into before his alleged suicide.
• Used by Karl Fairburne in Sniper Elite V2. Karl's investigating locations of V2 rocket launch sites in Berlin. Problem: It's the final days of the war, and any pieces of info that haven't been destroyed by bombings have been burned by the Nazis. While searching through an office, Karl finds a notepad whose top pages have been torn away and uses this trope to figure out what was written there.
• One of the game paths in SPY Fox in Dry Cereal involves finding the code to an item that can disarm William the Kid's Milky Weapon of Destruction. With the original destroyed, Spy Fox has to do this using his office easel - which doubles as an in-game paint tool in the other paths.
• Used by Lee in one episode of The Walking Dead to get instructions for how to drive a train from a ripped notepad.

Web Original

• In the Creepypasta Easter Egg: Snow on Mt. Silver, the sister learns the redacted GameShark code by holding the paper up to a light to see the indentation.

Western Animation

• In The Little Rascals episode "The Case of the Puzzled Pals", Alfalfa and Darla find such a clue via pencil rubbing on the notepad Spanky used in taking a call from his mother.
• Phineas and Ferb has Candace use this when she and Stacey are trailing the boys in England, referencing Sherlock Holmes when they find a notepad with half a page torn off. Candace shades the page underneath to reveal the full message and the location of Phineas and Ferb.
• An old episode of Scooby-Doo has Fred, Velma, and Daphne come across someone's diary whilst looking for clues. They find that the ink of the text has faded, but the pressure of the pen has worn through to the next page. So one of them grabs a coal and shades the paper to see what was written.

Real Life

• Used as a real technique by police, should the circumstances happen to suit it. There are machines called electrostatic detection devices which are able to do a considerably better job than the pencil-rubbing method.
• In many typewriters, the ribbon will have the shape of the letters typed clearly visible where ink was pushed off for the letter that was printed. Unrolling the ribbon would allow someone to see what's been typed.
• Queen Elizabeth II apparently used (emphasis on used, given that modern writing implements made it obsolete) black blotting paper to avoid that variant of this trope.
• There tend to be strict regulations against using any surfaces allowing that when composing secret documents.

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