Tapetum Theme

58 themes for VS Code and Open VSX, drawn from things that actually make colour.

Almost every animal that hunts at night carries a mirror behind its retina. Light that would have passed straight through is thrown back for a second pass, so almost none of it is wasted. It is why a cat sees where we see nothing, and why its eyes flare when a torch finds them.

The mirror is called the tapetum lucidum, and every animal throws back its own colour: green in cats, blue in horses, red in alligators, white in spiders. 1 structure, and no 2 of them look alike.

You also spend your nights looking at light. This is a collection of ways to throw it back: 28 families, each in a dark and a light variant, plus a high contrast pair for Coherence.

Families

Selenium

Selenium toning shifts the blacks of a silver print toward purple and stretches the tonal range at the same time. The result is an image that is warm in the shadows and cool in the highlights at once. So this family does not pick 6 separate hues. It picks a ladder of lightness and lets the hue rotate as the ladder descends.

Hadal

Water eats colour by depth. Red is gone by 5 metres, orange by 20, yellow by 50, green by 100, and below 200 there is only blue. Hadal makes that the rule: the colours that survive deepest get the most light and the most saturation, and the ones that die shallow are left faded on purpose. The red is almost grey, and it should be.

Effect

Pure code and code that touches the world look identical in every theme. Here they do not. Await, async, throw, catch and every mutation burn. Functions that only compute, the types, and the data stay cold. It is the same idea a type system uses to track effects, except you can see it without reading a signature.

Dichroic

A dichroic filter absorbs nothing. It splits. What passes through has one colour and what reflects has exactly its complement, and there is no third. Structure travels through the filter and takes the teal, data reflects back and takes the magenta. That is the whole palette. The terminal is the one place that breaks the rule, because red and green have to stay red and green.

Cochineal

Cochineal is a scale insect that lives on cactus, and carminic acid is what it makes to keep ants away. It gave Europe its first true scarlet, worth close to silver by weight, and it took about 70000 insects to make a pound of dye. The background is the crimson sunk into the cloth, the syntax is the same dye at different strengths.

Aerogel

Aerogel is 99 percent air and scatters short wavelengths the same way the sky does. Look at a block against a dark background and it is blue. Hold it up to a lamp and the light that gets through is amber. Same material, 2 colours, so the dark variant is the reflection and the light variant is the transmission. This is the only pair here that comes from 1 physical fact rather than 2.

A quick tour of all 58

Every theme in the collection, applied live while scrolling the picker.

The dark half. 28 of them, each drawn from something in the physical world that emits or bends light: emission lines, phosphor, anodised metal, deep sea bioluminescence, the blue glow of a reactor pool. No 2 of them share a palette: across the 6 roles that carry a hue, the closest pair still averages 12 dE apart, so switching family is a real change and not a shade of one.

The light half. Not inversions of the dark ones. A colour that reads clearly on black is often unreadable on white, and the reverse holds just as firmly, so every light palette was placed by hand and measured on its own ground. Same families, same sources, different physics.

Anodise

Anodised titanium has no pigment in it at all. The colour is an oxide layer a few hundred nanometres thick, and which colour you get depends only on the voltage: bronze around 20 volts, violet at 30, blue at 40, gold at 70. The metal underneath never changes. Anodise is the quietest family, all interference and no dye.

Borrow

Rust made a whole language out of one question: can this change, and who is allowed to change it. Borrow puts that question on the colours. Constants and anything read only are cold. Reassignable variables are warm. Parameters are borrowed, so they are green and italic. And at the exact point where you write into a variable, the name lights up. You stop looking for mutation and start seeing it.

Cavitation

Drive a bubble in water with sound and it collapses in under a nanosecond, reaching temperatures people still argue about, and emits a flash of light. Nobody fully agrees why. The flash is blue white and almost too fast to measure. Cavitation is the quietest palette in the collection, cold and low in chroma, with 1 hot colour for the core.

Cherenkov

A particle moving faster than light does in water drags a shockwave of light behind it, and that is the blue glow in a reactor pool. The intensity rises as 1 over lambda squared, so the shorter the wavelength the stronger it gets, which is why it looks violet blue. There is not a single warm colour in the code, because the physics does not produce one. The terminal keeps its red and yellow, and so do the error and warning marks, because those have to mean what they have always meant.

Cinnabar

Before synthetic chemistry, colour was something you dug up and ground. Cinnabar is mercury sulfide and gave the vermilion of Pompeii. Orpiment is arsenic and was the only clean yellow for 1000 years, poisonous enough that painters avoided mixing it with lead. Malachite, azurite and lapis came out of the same kind of rock. Warm and heavy, because pigment is.

Coherence

A mixed argon and krypton ion laser puts out 6 visible lines from 1 tube at once, which is what a white laser actually is. Argon gives 457.9, 488.0 and 514.5 nm, krypton gives 413.1, 568.2 and 647.1. Every colour in the code is one of those lines. There is no magenta anywhere in it, because magenta is not a spectral colour and no laser can emit one, so the terminal's magenta slot carries the krypton violet instead. The interface falls to true black so the only thing emitting on the screen is the code.

Epitaxy

A polished silicon wafer is a dark mirror with a violet cast, and that is the background. The syntax colours are the real emission peaks of the materials grown on top of it: GaN at 405 nm, InGaN at 450 and 505, GaP at 555, AlGaInP at 590, AlGaAs at 660. The light variant is lit the way a cleanroom is lit, in yellow, because photoresist cannot see that end of the spectrum.

Fraunhofer

In 1814 Joseph von Fraunhofer pointed a prism at the sun and found hundreds of dark gaps in the spectrum. They are elements in the sun's own atmosphere eating their own colours on the way out. He labelled the strongest with letters and those letters are still in use. Fraunhofer is the brightest family here, built around the sodium D line, the hydrogen alpha and the magnesium triplet.

Glacier

Glacier ice is blue because pressure squeezes the air bubbles out, the light path gets long, and red is absorbed on the way through. The older and more compressed the ice, the deeper the blue. Nothing in this family drops to black, not one surface, because nothing in a crevasse does either. The warm colours are the sun on the surface and the rock band running through it.

Incandescence

Heat steel and it tells you its temperature. Dull red around 600 degrees, cherry at 750, orange at 900, amber at 1000, almost white by 1300. Blacksmiths read it by eye and still do. In this family lightness is temperature, so the ladder is not an aesthetic choice, it is the scale. The 1 cold colour is the blue at the base of the forge flame.

Noctiluca

Living light is nearly always blue green, because that is what travels furthest through seawater. Dinoflagellates glow at 480 nm and turn a breaking wave into a line of fire. Jellyfish green fluorescent protein sits at 509 and won a Nobel prize for being useful. Fireflies are further toward yellow. The red is the rarest thing here: 1 Brazilian beetle larva, the railroad worm, is the only land animal known to make it.

Palimpsest

A palimpsest is a parchment scraped clean and written over, with the old text still faintly readable underneath. Keywords, imports, punctuation and type annotations are the scraped layer here, pushed back toward the background. The names you chose and the data you wrote are the new text. Roughly 2 thirds of the screen recedes on purpose.

Passepartout

A passepartout is the card mat around a framed photograph. It is not decoration, it is what makes the eye fall on the picture. Every theme puts the interface at the same brightness as the editor or darker. This one inverts it: the mat is far lighter than the plate, and the editor sits inside it as the print.

Persistence

Oscilloscope phosphors are graded by how long they keep glowing after the beam has moved on. P1 is the willemite green everyone pictures, P7 goes blue then fades to a long yellow ghost, P11 is the blue used for photographing traces. Persistence is the green one, and the warmer colours are the ghost that P7 leaves behind.

Provenance

Every theme in the world colours by grammar. This one colours by where a symbol came from. What you defined here is gold and bold. What the language handed you is cyan and italic. What cannot change any more is violet. The rest of your own code is a single colour, and the keywords are deliberately dimmed, because you already know that function is a function. Open a file and you see instantly what is yours and what is borrowed.

Quantum

Heat a gas and it does not glow across the spectrum, it glows at a handful of exact wavelengths and nothing in between. Hydrogen gives you 4 visible lines, neon gives you a fistful of reds, mercury a violet and a green so specific they are still used to calibrate instruments. Quantum takes its violet, blue and teal from that idea: a small set of exact positions rather than a smooth range.

Riso

A Riso duplicator does not mix colour. It pulls 1 pass per ink and lays them over each other, slightly out of register. The inks come from a fixed catalogue you order by name, and the fluorescent pink is impossible to mistake for anything else. These are 6 of them, printed on kraft.

Safelight

Photographic paper cannot see the deep amber of an OC filter, which is why it is the only light you are allowed to switch on in a darkroom. You learn to read everything from one colour and how bright it is. Safelight works the same way: the code is a single amber in 4 intensities, and the only real colour in it is the red of the filter itself, kept for literals.

Silverpoint

Silverpoint is drawing with a silver stylus on prepared paper. There is no colour, only line and tone, and no way to erase. Leonardo and Durer worked in it. This family has no hue in the code at all: 6 greys, plus weight and italic doing the work that colour usually does. The interface keeps a single silver blue accent so you can still find your cursor.

Stratum

A road cut through sediment is read by depth, not by content. Each band is a different million years. Stratum takes the colour off the syntax entirely and puts it on nesting depth: the code itself is 1 sandstone in 6 tones, and all 6 real colours are spent on bracket levels and indent guides. You see how deep you are without counting.

Valence

Dissolve a transition metal and the water takes its colour. Permanganate is a violet so intense a few grains stain a litre, dichromate is orange, copper is sky blue, nickel green, cobalt chloride a deep blue that turns pink when it picks up water. These are transmission colours, not emission, which is why they read deeper and heavier than the rest of the collection.

Verdigris

Copper does not corrode into one colour, it corrodes into a catalogue. Verdigris is the blue green of an old roof, malachite the deeper green of the ore, azurite the blue, cuprite the brick red of the first oxide layer, bornite the purple tarnish that gives peacock ore its name. Brass sits underneath as the metal before any of it happened.

6 ways of colouring code

Almost every theme in existence answers a single question: what kind of symbol is this. Keyword, string, number, type. Tapetum ships that one and 5 others, and the answer is a property of the theme, so changing theme changes the question.

grammar  ·  22 families
What kind of symbol it is. The classic, and what nearly every theme does.

provenance  ·  Provenance
Where the symbol came from. Gold and bold for what you wrote here, cyan and italic for what the language handed you, violet for what cannot change. Keywords are dimmed, because you already know function is a function.

borrow  ·  Borrow
Whether a value can change. Cold for frozen, warm for mutable, green and italic for borrowed parameters, and a name lights up at the exact point you write to it.

effect  ·  Effect
Whether a line touches the outside world. await, async, throw and every mutation burn. Pure computation stays cold.

signal  ·  Palimpsest
Signal against boilerplate. Keywords, imports, punctuation and type annotations are scraped back toward the background. Only the names you chose and the data you care about stay lit.

tone  ·  Stratum, Silverpoint
Nothing at all. No hue in the code, only 6 tones plus weight and italic.

3 of these read your language server rather than the grammar. provenance, borrow and effect use the semantic tokens it emits, including the declaration, defaultLibrary, readonly, static, modification and async modifiers that most themes never touch. They fall back to grammar rules when no server is running, so open a real file rather than a scratch buffer the first time you try one.

In grammar, 6 roles carry their own hue: keywords, strings, functions, types, numbers and tags. Parameters and properties take the foreground colour and are told apart by italic instead, because a 7th saturated hue cannot be held away from the other 6 without washing all of them out.

How they are checked

Colour is a judgement call, so every value here was placed by hand. An earlier version let an optimiser choose them and it converged on something worse: 2 of the families came out under 2 dE apart, and it had bleached the keywords to near grey chasing its own objective.

What a machine is good for is catching what a person misses. On all 58 variants:

None of that comes from a hand written list. tools/extract-keys.mjs reads the colour registry out of every window bundle of the installed editor, including the sessions window that 1.136 moved into a bundle of its own, and records which keys are deprecated. tools/extract-pairs.mjs reads every stylesheet and collects each foreground and background used in the same rule, so what gets checked is what the editor actually paints together. tools/extract-derivations.mjs reads the keys whose default is another key, which catches the class of bug where a value quietly contradicts the surface beneath it. The 3 files they write are committed, checked in CI against every theme, and refreshed by a weekly workflow that downloads the current VS Code build, so a new surface is noticed by a machine rather than by a person.

The same measurements run against the editors that install from Open VSX, and against the other platforms. The current VSCodium, Cursor, Windsurf, code-server, Positron, Kiro, Trae, Antigravity and Void builds were each read the same way, registry, stylesheets and derivations, and every theme checked on every one of them; the keys their older cores do not know yet are ignored by them, and the 35 surfaces those editors paint in colours of their own, listed with their reasons in tools/forks.mjs, take the family's colour instead. The Linux and Windows builds of VS Code 1.136.0 carry the same registry, stylesheets and derivations as the macOS build, byte for byte, so what holds on one holds on all 3.

node tools/analyze.mjs    # all 58, against the real pairs
node tools/audit.mjs      # structure, schemes, manifest, files and this README
node tools/compare.mjs    # against every theme Microsoft ships

Install

code --install-extension tuguidragos.tapetum

Or from the VS Code Marketplace, or Open VSX, which is where VSCodium, Cursor, Windsurf, Positron, Kiro, Trae, Antigravity, Void, Gitpod, code-server and Theia install from.

Press Cmd K then Cmd T, or Ctrl K then Ctrl T on Windows and Linux, and type a family name to filter. Every family is Tapetum <Family> for the dark variant and Tapetum <Family> Light for the light one.

Making one your own

Any colour can be overridden per theme, without forking anything:

{
  "workbench.colorCustomizations": {
    "[Tapetum Quantum]": {
      "editor.background": "#080B14"
    }
  },
  "editor.tokenColorCustomizations": {
    "[Tapetum Quantum]": {
      "comments": "#7580AD"
    }
  }
}