There's a lot of symbolism associated with color. From red being the color of violence, heroes, or evil, to purple being associated with grace, power, and magic, all colors have some special associations and meanings beyond just being pretty to look at. The color gray is no exception, being the color of many things and having many meanings. One of those associations is sadness.
Maybe it's just because, unlike the bright and cheery colors of the rainbow, gray can seem dull and dreary in comparison. Maybe it's because the gray-and-white color palette of winter can come with "seasonal depression" and gray clouds bring rain and a lack of sunlight. Or, maybe it's just because it's lacking any "real" color, and can thus be used to convey a "lack" of emotion or happiness.
Whatever the reason, the color gray ends up being used as a shorthand for characters being unhappy- if not clinically depressed, then just down in the dumps and needing a hug. And sometimes, they're completely emotionless! Downplayed examples may instead associate gray with boredom, a feeling heavily associated with depression while having less stakes. Regardless of the specific mood it's meant to symbolize, gray is associated with all feelings that may be considered "dreary" or "glum".
A common tactic used by medicine commercials is to portray the world as gray and miserable until the commercial's narrator takes the advertised product, suddenly lighting up the world around them. Thus, the gray world is used as a metaphor for being stuck with allergies, depression, heart problems, etc., and the colorful world is the world when everything is happy and perfect. This "world brightening" affect is used by other works as well to show the end of the depression, or at least the beginning of things getting better. Alternatively, something turning gray symbolizes the opposite- the start of sadness.
Subtrope of Colour-Coded Emotions. Supertrope to Gray Rain of Depression, when gray rain is used to exaggerate a bad mood, and Grave Clouds, where cemetaries are dreary and gray. Overlaps with Deliberately Monochrome.
Anime and Manga
- The Downer Beginning of Kotoura-san anime applies a progressively grey desaturation filter to mark Haruka's progressive, downward spiral of broken-ness that was brought by a power that she couldn't turn off. The beginning of her journey towards Heal the Cutie is symbolized by the shattering◊ of this filter, which is at a graphite colour at this point.
- The Little Mermaid (1989): In the aftermath of King Triton's Unstoppable Rage, Ariel's secret grotto turns from a cool undersea blue to a chalky gray.
- Trolls: The Trolls' colorful bodies turn gray when they're depressed. Branch is gray for most of the film, while Poppy and the others turn gray when they they're captured by Chef and seem doomed to be eaten.
- In Unedited Footage of a Bear, the Claridryl ad starts with Donna's world being full of gray and muted colors, until she "stands her ground" with Claridryl and lights everything up. As the film is a parody of drug commercials, there are numerous hints that Donna is suffering from depression after the death of her husband, and the grayscale beginning of the commercial symbolizes this issue and how Claridryl helps her...with some side-effects.
- N. K. Jemisin's Inheritance Trilogy: Discussed when Yeine creates an offshore castle. She makes it uniform grey at first, but adds colours and plants when someone drily asks if she wants the inhabitants Driven to Suicide.
- In Kishmish by Teffi, the main character, a little girl, gets scared when she wakes up before dawn and muses that "if dreariness and fright get translated into color, it will be a vague grey darkness".
- Malinda Kathleen Reese: In "An Honest 2020 Christmas Song", there are two Malindas singing: An optimistic one whose segments are in color, and a depressed cynic whose segments are in gray. The video switches color rapidly whenever one of them changes the mood.
- Taylor Swift: The Colour-Coded Emotions in the song "Red". The passion of loving is associated with red, the sadness of losing with blue, and the loneliness and depression of missing is dark gray.
- Chronicles of Darkness: Depression shows as a grey glow to emotional Aura Vision powers.
- Dungeons & Dragons:
- The Neutral Evil afterlife in the default cosmology is Hades, a gloomy grey landscape with a sunless grey sky where the dead lose their colour and sink into eternal despair.
- Eberron: Dolurrh, the Realm of the Dead, is a grey wasteland that leeches the colour and emotion out of everything that enters. Shades and incautious visitors soon succumb to complete apathy.
- Pathfinder: Gnomes who don't get enough excitement and novelty in their lives suffer "the Bleaching", which turns their skin, hair, and eyes grey and ultimately causes Death by Despair.
- Pokémon Sword and Shield gives the previously-introduced pink and perky coral Pokemon Corsola a Galarian form: a gray and white, red-eyed, sad-looking Ghost-type. The species had nearly gone extinct in Galar due to environmental change, evoking real-life coral bleaching.
- In The Sims 4, the "Bored" moodlets have a gray color. If a Sim is bored, the UI near the Sim turns gray and they need to do something fun to feel better.
- Cans Of Beans: Carl's Mental World is in greyscale when he's sad and lonely, but gains colour when he starts to open up to Dude.
- Erfworld is set in an RPG-Mechanics Verse where a character's appearance is linked to their disposition and true nature. Characters who have suffered a terrible trauma and not yet recovered turn ash-grey; in Wanda's Darkest Hour, she also becomes withered and emaciated.
- In Homestuck, where every character has a theme color, Karkat's color (used in his text color and clothing) is gray, fitting with his cynical and self-loathing nature.
- Widdershins: When a spirit of Sloth traps Mal in a memory of his Dark and Troubled Past, Mal becomes desaturated as he starts to give up on helping his friends. The memory is also in greyscale — because Mal is colour-blind, but it conveys the bleak atmosphere to the reader.
- On Neopets, the "Gray" paintbrush color is universally associated with sadness. The gray pets all look unhappy, with red, puffy eyes and drooping body parts. The gray faeries have no magic and are always sad. Even items, such as gray-colored food, are either said to make you sadder or are themselves limp and miserable. To hammer it in, pets will occasionally ask you "paint them gray" if you're going to keep leaving them unhappy.
- Drew Gooden: In one video, Drew's obsession with awful life-hacks leads his wife to abandon him. The colors turn gray as he monologues about how lonely he is...before deciding to just transition into the rest of the video.
- Kurtis Conner: In a collab with Danny Gonzalez and Drew Gooden, they're poking fun at an account called "Tiktokids", which they note kind of sounds like "took the kids". This transitions into sad piano music and the video's colors turning gray as they joke about how "she took the kids".
- Twisted Translations: A common visual gag in the videos is for the colors to turn gray as soon as the song gets unusually depressing for a moment, like spontaneously referencing death or anxiety.
- Cream Heroes: TT is a pale grey tabby with sad looking eyes. She tends to be the grouchiest of the cats, punching those who get in her personal space as well as meowing and hissing whenever she has to have a bath or go to the vet.
- OK K.O.! Let's Be Heroes: In "Rad Likes Robots", when Rad says he never loved Shannon, she's heartbroken and her reset button and eyes turn from red to gray.
- Richard from Unikitty! is a gray-colored LEGO brick with a dour personality, contrasting the brightly colored and far-more optimistic others.