The colours of art history, dated and cited — a tool that argues only against a claim, never for it
Every colour has a birthday. Egyptian blue was fired before writing kept recipes; Prussian blue was an accident of 1704; titanium white could not exist before the First World War. Because a pigment cannot appear in a painting made before the pigment itself existed, the palette is a clock — but a one-directional one. A colour that is too new for a claimed date is strong evidence against it. A period-consistent palette proves nothing. This room holds each pigment as a machine-readable fact: what it is, when it first appears, and when it could not yet be — every figure carrying its source and a truth status. No keys, no database, no funds, no take-rate.
Pigment dating is the most honest tool in authentication precisely because of what it cannot do. Find synthetic ultramarine (1826) in a canvas signed 1650 and you have caught an anachronism — the pigment did not exist. But find only period-correct colours and you have proven nothing: a skilled forger reads the same books. This asymmetry is not a limitation to hide; it is the whole truth of the method, and it is printed in-band on every answer this room gives.
And the dates themselves carry uncertainty. First-attested floors rest sometimes on a single early object; invention years are occasionally debated by a few years; some pigments — vermilion, ultramarine — exist in both an ancient natural form and a later synthetic one that only a laboratory can tell apart. Where a source merely declares, we say source-declared; where sources fight, contested. Real identification needs XRF, Raman, a cross-section. This is the reasoning layer above that lab, not a replacement for it.
Pick the pigments identified in an object, give the date it claims to be, and read each colour against its own first-attested floor. Remember which way the evidence runs.
Swatches are honest sRGB approximations only — real appearance depends on grade, grind, binder, layering and age, and effects like Egyptian blue's near-infrared glow cannot be shown on a screen at all. Every date and story carries its source and a truth tag.
Everything here is one curl away, and the anachronism check answers with its honest asymmetry in-band — informational_only, a not_authentication note, and the cited floor for every pigment. Nothing is stored; nothing needs a key.
The verbatim endpoint contracts live at /api/pigments.