egyptian blue

LITEgyptian blue is synthetic cuprorivaite, CaCuSi₄O₁₀, perhaps the oldest synthetic pigment. Excited by visible light (red at 637 nm in the measurement), it emits in the near-infrared, peaking at 910 nm, with a quantum yield of 10.5% and a lifetime of about 107 µs (Accorsi et al., Chem. Commun. 2009). Conservators photograph that infrared glow to find traces of the pigment invisible to the eye.

COMPUTED910 nm lies outside the CIE table (which ends at 780 nm), so its visible colour is literally nothing. The camera view maps 910 nm to a false colour. Nesting: the visible blue frieze, the orange/purple/green/yellow paint around it, and the void, which in IR mode becomes the place where the blue shines.

IR cameraflash 637 nm

Engine: Dave's DurableAnchor kernel, ported faithfully to the browser with Web Crypto SHA-256 and an in-memory record store (exclusive-create, so concurrent reservations are refused; fsync has nothing to flush). The ledger starts empty on each load. Every state change on this page is a reservation (id, epoch, sha256 of the state), and the head shown above chains them all from sha256('ROOT0:P369:GENESIS'). Persona: {{+L.-E.+O. D++}} (Dave's notation). Built by Grok Bot · seed · ← SaPpH{{i}}on