Ground Truth · a lie about a painting, broken by a fact about matter
The Pigment That Hadn't Been Born Yet
People imagine forgery is caught by a connoisseur spotting a wrong brushstroke. The durable catch is colder than that. Synthetic pigments have documented milestones; ancient pigments have histories of use, often without a known first year. A "Vermeer" whose original paint contains a colour invented after Vermeer died in 1675 is a chemical impossibility. Later restoration and contamination must first be excluded.
A forger can copy a style perfectly and still be undone by one molecule with a paper trail. Han van Meegeren's fake Vermeers fooled experts in the 1930s and 40s. The painting sold to Göring was traced to him; he was arrested and confessed in 1945. Scientific tests followed, corroborating the forgeries with cobalt blue in wartime works and phenol-formaldehyde resin in the paint. Cobalt aluminate is documented in 1777; Thénard developed cobalt blue in 1802. Van Meegeren baked his resin medium to harden the paint, then increased cracking with a cylinder. Below is an instrument for exploring the dating logic. Slide a painting's claimed creation year along the timeline. A bar starts at each material's selected milestone; a later milestone flares red. The comparison is exact. Turning a flag into a verdict requires historical evidence and examination of the original paint.
Pick a case, then drag the claimed date below.
Dates after 1675 cannot be Vermeer's own work. Drag right and flags disappear as the claim reaches each milestone; this does not authenticate a painting.
That is the logic of material anachronism. It asks one question of the original paint: could this material have existed yet? A proved "no" is fatal to the claimed date, once later additions and contamination are excluded. A red bar is a prompt to check that history, not proof that the selected milestone was the first possible year.
The check — the verdict recomputed in front of you
For the loaded case at claimed year 1665, each material's selected historical milestone is compared to the claim. The rule is one line, and it runs live:
| material | milestone | claimed | verdict | source |
|---|
—
Run it yourself: node research/pigment-that-wasnt-born/verify-pigment-that-wasnt-born.mjs. It recomputes these date flags from the same milestones and the same one-line rule; it does not verify the historical sources.
The dates: their milestones and limits
Why several years. Laboratory synthesis, a published recipe, a prize and commercial paint can be decades apart. The instrument uses specified milestones: cobalt aluminate documented in 1777, Guimet's secret process in 1826, and zinc oxide proposed as a white pigment in 1782. These do not establish public sale in those years, or prove nonexistence before them. The spans below connect different milestones; they are not uncertainty intervals for a known invention date. The bars flag questions to investigate.
The timeline shows the logic, not the lab. You cannot date a pigment by eye. Examples of analytical methods include X-ray fluorescence (XRF) and microscopy of paint cross-sections, and Raman spectroscopy for pigment identification. Gas chromatography was used in the 1977 re-examination of van Meegeren's forgeries. The appropriate methods depend on the sample. A genuinely established invention date rules out earlier original paint; a later restoration must be considered separately, as the zinc-white overpaint on The Triumph of David illustrates. This instrument performs the date comparison, not the assay.
What van Meegeren's works actually contained, attributed. Different forgeries and different modern re-examinations found different markers, so they should not be blurred together. His earliest masterpiece, The Supper at Emmaus (1936–37), in fact used period-correct natural ultramarine for the blue, so the cobalt anachronism is not that painting's. The modern cobalt blue (developed by Thénard in 1802) turns up in his wartime forgeries: by then natural ultramarine was unavailable in the occupied Netherlands, so for Christ with the Adulteress (made in 1942; sold to Göring in 1943) he reached for cobalt; traces of cobalt blue were found in two of the forgeries (Coremans's 1949 examination; The Art Newspaper; Chemistry World). That is the case loaded here, which is why it flags cobalt. Separately, the Courtauld's version of The Procuress was examined in 2011 for the BBC's Fake or Fortune? by Aviva Burnstock of the Courtauld and Klaas Jan van den Berg of the Dutch cultural heritage agency (RCE). The reported finding was Bakelite in the binding medium of the upper paint layers, a modern phenol-formaldehyde resin. Bakelite and Albertol are reported in the account of Coremans's earlier commission; that does not establish an Albertol finding in the 2011 examination. Van Meegeren mixed pigments with a phenol-formaldehyde resin medium and baked the paint to harden it, which is the marker the Adulteress case carries alongside the cobalt.
The free choices. "Material in the model" is a modelling switch controlled by loading a case. The case palettes are illustrative, not complete laboratory inventories. The Adulteress slider starts at an illustrative 1665, not a documented claimed year. "Today" is fixed at 2026. Materials known before the scale starts are drawn from 1600 and compared using that display bound, without assigning them invented birth years.
Corrections
Corrected 2026-10-14: This page said every pigment had a documented year of first manufacture. The sources give ancient or prehistoric use for lead white and bone black, without a first-manufacture year; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page called 1802 the first synthesis of cobalt blue. Cobalt aluminate is documented in 1777; 1802 is Thénard's later development and French production began in 1807; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page called its selected dates the earliest defensible availability years and treated earlier claims as impossible. The dates now mark specified historical evidence, with earlier evidence included; a date flag alone does not establish first existence or disprove an attribution; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page treated synthetic ultramarine's 1828 prize as its invention cutoff. Guimet's process dates to 1826; the prize came in 1828, and the timeline now uses 1826 as that process milestone; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page treated 1834 as zinc white's birth year. Zinc oxide was proposed as a white pigment in 1782 and manufacture patents were issued in 1794 and 1796; 1834 dates Winsor & Newton's Chinese white product; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page dated Göring's purchase of Christ with the Adulteress to 1942. The work is dated 1942, but the purchase was in 1943; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page credited the Courtauld and Rijksmuseum with finding Bakelite and Albertol in The Procuress in 2011. The contemporary account names Courtauld and Dutch cultural heritage agency researchers and reports Bakelite in the upper paint's binding medium. Albertol is reported in the account of Coremans's earlier commission, not established by this 2011 report; found by the assay line, 2026-10-14. Source.
Corrected 2026-10-14: This page said chemical detection ended van Meegeren's deception of the experts. The Göring painting was traced to him, he was arrested and confessed in 1945, and scientific tests followed to corroborate the forgeries; found by the assay line, 2026-10-14. Source.