A field catalogue · twelve pigments · for the conservator and the curious
Earth, Ash, and Lake
A ledger of historical colour: where it was dug, boiled, struck, or stolen; how it behaves in the binder; and why some hues leave the picture while others refuse to die.
Prologue
Colour, in the shop, was never an abstraction. It arrived as a stone wrapped in paper, a cake that stained the nails, a lake settled on chalk like scum on a dye-bath. Painters named their materials after places and corpses and kings because that is how the stuff entered the room. This catalogue keeps those names and adds the quieter ones — mineral, organic, synthetic — so that a reader can sort the drawer without pretending the drawer was ever tidy.
Three families organise what follows. Earths are the ground world: ochres, green earth, the crushed metamorphic blues. Ashes and soots are fire’s remainder, and with them the calcined bones and the charred vine. Lakes are colour struck onto a pale corpse of alum or chalk — dye made to sit still on a brush. The twelfth entry, a modern blue born of a botched red, is here to mark the moment the shop began to smell of the laboratory rather than the yard.
How to read this catalogue
Each entry carries an origin and a hazard. Origin is a working fiction: vermilion may be a mineral or a sublimed twin of that mineral; indigo is a plant that behaves, on the palette, like a stone. Hazard means the dry colour as handled in a studio, not the finished, bound film. Gentle is not a promise. It means only that the pigment is not the one that should send you to the fume cupboard first.
Use the facets to thin the drawer. Open the conservation note when you need the incompatibilities. The colour study is a larger field — no photograph can be trusted with these hues, so none is offered. Grid view keeps the specimens as cards; ledger view lines them up so the names, origins, and first sentences can be compared across a single measure.
Showing the full drawer of twelve.Mineral earths and stones only.Organic colour — lakes, vats, and the once-living.Laboratory inventions after 1700. Handle as poison. The quieter drawer.
NameOriginHazardOpening
01 · Afghanistan · before 600
Natural Ultramarine
Lazurite · lapis lazuli
Mineral
Gentle
Ground from lapis mined at Sar-e-Sang in the Kokcha valley, and priced, in medieval contracts, above gold. Painters kept it for the Virgin’s mantle; the leftovers were sold as a greyer “ultramarine ash.”
Conservation and chemistry
Lazurite is a sulfur-bearing tectosilicate: the fire of the blue is charge-transfer among sulfur anions in the sodalite cage. It is stable in oil and fresco. Do not confuse it with azurite, which greens as it becomes malachite. Guimet’s synthetic of 1828 ended the monopoly, not the affection.
Whether the ground mineral or the sublimed synthetic, this is mercury’s red: dense, slightly orange, and prone to a surface dusk where chloride or strong light converts it toward metacinnabar.
Conservation and chemistry
Illuminators bound it in glair; panel painters in oil, where it dries reluctantly unless cut with a lead drier. Blackening is a documented vice, not a myth. Handle as mercury. Never heat the dry colour in an open room.
Basic lead carbonate, grown in pots over vinegar and dung. The decisive European white until the twentieth century: warm, heavy, and a catalyst in oil, which is why old grounds are so often lead grounds.
Conservation and chemistry
It yellows in prolonged dark and blackens to sulfide in foul air. Titanium and zinc replaced it for safety, not always for behaviour. Poisonous to make and to sand. The film, once bound, is another question; the powder is not.
Arsenic trisulfide, a crystalline honey from lemon to gold. Manuscripts and Persian miniatures used it as a cheaper sun. It is a poor drier and a bad neighbour to copper and lead, which it blackens.
Conservation and chemistry
The name is only auripigmentum worn down. Realgar, its orange cousin, shares the arsenic and the manners. Isolate it in reconstructions. Treat every crumb as arsenic.
A low-chroma celadon crushed from Verona and the Aegean. It cannot make a shouting green; that refusal is the point. In Italian fresco it is the underpaint of flesh — verdaccio — a cool death on which life is glazed.
Conservation and chemistry
Stable, lean, slightly transparent. Conservators trust it because it almost never misbehaves. Do not expect it to stand in for verdigris or the arsenic greens; it is a different sentence.
Recovered from the glands of murex snails in a process Pliny records with industrial nausea. Tens of thousands of animals for a cloak. The vat stinks in reduction; the cloth, lifted into air, blues and then reddens as it oxidises.
Conservation and chemistry
A vat dye more than a painting pigment, though lakes were struck from it. Rank itself is this molecule’s doing. Lightfastness of the true purple is respectable; surviving textiles have outlasted empires that wore them.
A greenish fire that lights Mughal painting and later European tubes. The colonial account — cows fed mango leaves, urine evaporated into balls — was treated as a fable and is now, uncomfortably, the best-supported one.
Conservation and chemistry
Production was banned in Bengal in 1908. Moderately lightfast for an organic yellow, which is faint praise. Modern substitutes match the hue and spare the animal. They do not match the story, which is not a reason to revive it.
Anthraquinones from madder root, precipitated onto alum and chalk. The strike runs from blush to blood with the mordant and the pH. It is the red of painted mouths and of roses that have already begun to leave.
Conservation and chemistry
Fugitive in tints, especially in oil. In 1868 Graebe and Liebermann synthesised alizarin from coal tar and collapsed the Dutch madder economy in a decade. Synthetic alizarin is not identical; purpurin was part of the old warmth.
From Indigofera and, in Europe, from woad. A vat dye first; as a pigment, the washed cake. A deep, slightly green hole in the picture. The Company’s plantations are part of the colour and cannot be left out of an honest drawer.
Conservation and chemistry
Reasonable in tempera; a known fading risk in watercolour and in lean tints. Do not confuse historical indigo with the later phthalocyanines, which share a category and almost nothing else.
Ground mummies, asphaltum, and the resins of the embalmers, sold in London and Paris as a transparent warm brown for glazing flesh. It cracks and darkens. Artists who learned what they were using put the tube down.
Conservation and chemistry
Ethically indefensible before one reaches the condition report. Burne-Jones is the usual anecdote; he was not the only one. Asphaltum alone will give you the vice without the grave. Prefer that, or prefer not to glaze with bitumen at all.
The first modern synthetic pigment: Diesbach, expecting a red lake from potash fouled with animal blood, got this ferocious blue instead. Cheap, transparent, high-chroma. Japanese aizuri-e after the 1820s is this blue arriving by sea.
Conservation and chemistry
Fades in alkaline fresco and in mixed tints with lead white under strong light, then may recover in the dark — a disconcerting habit. Not a fresco colour. In oil it is a glory if you accept the staining power.
An electric, slightly yellow green that no earth can match. It killed men in the wallpaper trade and dusted off damp flock in ballrooms. Impressionists used it anyway. It blackens beside sulfur-bearing neighbours.
Conservation and chemistry
Do not grind it in an open studio. Scheele’s green is the older, related vice. Viridian and the phthalocyanines are the living substitutes. When you see this hue in a nineteenth-century picture, read the craquelure as a warning label the painter ignored.
A fugitive pigment is not a failed one. It is a colour that keeps a different time from the picture. Madder leaves the tints first. Indigo, in a watercolour sky, may go to grey in a south window while the earths beside it stay. Prussian blue performs a small resurrection in the dark. Conservators describe these habits without scolding the dead; the dead were buying what the shop sold.
Lightfastness ratings are a modern courtesy. The older courtesy is to know which passages were meant to burn and which were meant to stay — the difference, often, between a glaze that was always a veil and a local colour that was meant to name a thing. This catalogue will not tell you what to restore. It will tell you what you are looking at when the rose is no longer a rose.
A blue with a red bone in it. Beside azurite it looks ecclesiastical; beside Prussian it looks mineral and slow. In oil it can be glazed over a blackish underlayer to a night that still breathes.
Heavier than it looks. Next to madder it is a door slammed; next to orpiment it is the fruit beside the coin. The dusk that comes with age is not dirt. It is chemistry finishing a sentence.
Not paper and not snow. A cream with weight. Mixed into almost every flesh in the European tradition, which is why those faces have a density titanium often misses.
Gold that has decided not to be metal. In a manuscript margin it reads as sunlight; in a large field it is almost loud enough to be vulgar, which is why it was used sparingly and with pleasure.
Not violet in the modern tube sense — a blood with a blue memory. On cloth it signalled a person you were not to touch. On a page it should still feel expensive, even when it is only a gradient.
A yellow that leans toward green as if remembering the leaf. In a highlight it can look lit from behind. That generosity is why it was loved, and not why it should be made again.
Closer to a well than to a sky. Used as a black by painters who found bone black too dead. The green in it shows only when you put it beside Prussian or ultramarine and let them quarrel.
A laboratory night. Stains the oil, stains the memory of the other blues. In a wash it can look like depth; in mass tone, like enamel. The first modern colour still behaves as if surprised to exist.
The green of a boiled sweet and a warning label. Nothing in the earth drawer prepares you for it. That is why it was invented, and why it should stay in the history of pictures rather than in the mill.