Colours sampled from three Edo-period artworks seen at the British Museum Samurai exhibition, 1 Mar 2026. Pigments: mineral verdigris (rokusho), iron-gall ink (sumi), cinnabar vermillion, Prussian blue (bero-ai), yellow ochre. These are the raw sampled values — a starting point for remapping Bristlenose's token system.
Tosa School, c. 1790–1810
Dominated by a distinctive soft blue-green (verdigris / rokusho) on the tatami and floor areas. This is paired with:
Utagawa Kuniyoshi, c. 1830s
Much more dynamic and saturated:
Utagawa Kuniyoshi, c. 1845
The most atmospheric of the three:
Prussian blue was made accidentally in Berlin, c. 1704–1706, when the pigment-maker Johann Jacob Diesbach (working with the alchemist Johann Conrad Dippel) was trying to produce a red lake and got a deep blue precipitate instead. It is the world's first modern synthetic pigment — "derived not from a natural, animal, vegetable, or mineral source, but from an artificial chemical compound" [1]. Chemically it is ferric ferrocyanide [1]. It was the first stable, lightfast, affordable deep blue since the recipe for Egyptian blue was lost in antiquity — before it, deep blue meant ruinously expensive ground lapis. A durable blue at roughly a tenth the price was a rupture in the economics of colour.
It reached Japan as a costly Western curiosity by the late 18th century, used sparingly for painting. Its Japanese names — bero / bero-ai / beroin — are a garbling of the Dutch Berlyns blaauw ("Berlin blue"): the pigment carries the echo of its birthplace in its very name [4]. After ~1820 the price fell, and steadily cheaper Chinese imports from the late 1820s finally made it affordable enough to use as a printing colorant [4] — the price crash is what moved it from the painter's cabinet to the mass-market print.
The Met's framing: the publisher Eijudo advertised Hokusai's Thirty-Six Views of Mount Fuji for New Year 1831 featuring "an exotic pigment newly available for the print market: Prussian blue" [2]. The Great Wave (from that series, c. 1830–32) was marketed as aizuri-e — blue-printed prints — with the blue an explicit selling point [3]. The MFA credits the pigment with stimulating Hokusai and Hiroshige to design their landscape series [1].
The nuance worth its weight in gold: spectroscopy shows the famous blue outlines of the Fuji series are not pure Prussian blue but a Prussian-blue / indigo mixture [3]. The most celebrated "Prussian blue" in art history is, on inspection, the new synthetic pigment married to the old plant dye.
Our two sampled Kuniyoshi triptychs (c. 1830s–1845) sit exactly in this window — the first
decade of cheap Prussian blue. Kuniyoshi's night-sea and ghost scenes depend on a deep,
non-fading blue that simply wasn't achievable at that saturation before the price fell. Sampling
#1E3A5F from those prints was sampling the blue revolution itself.
Edo already had a profound blue culture: indigo (ai, 藍) and the aizome dyeing tradition so saturated the city that a visiting chemist coined "Japan blue" for it. The genre name aizuri-e literally means "indigo-printed picture" (藍摺絵) — yet it came to denote prints made with the synthetic Prussian blue, which displaced native indigo and dayflower from the 1820s because it was more vivid, stronger, and didn't fade [5]. The new colour wore the old colour's name.
Hokusai's blue-drenched prints flooded Europe and helped ignite Japonisme; the Great Wave informs Van Gogh's Starry Night and shadows Picasso's Blue Period [6]. Beyond art, the same compound is the chemistry of the cyanotype / blueprint (Herschel, 1842) — which is why engineering drawings were ever called "blueprints." A colour born in a lab that became the sea in Japan's most reproduced image, then the technical drawing of the industrial age.
Why it earns the Edo accent
1. First synthetic colour → an accent marking the birth of manufactured, reproducible colour — quietly fitting for a software tool.
2. The new pigment wearing the old dye's name (aizuri-e = "indigo print," made of Prussian blue over indigo) → the exact metaphor of Edo: warm traditional washi paper (the past) + an engineered blue (the tool). The palette re-enacts the pigment's own history.
3. The colour that circled the globe (Berlin lab → Hokusai's wave → Van Gogh → the blueprint) → a small, deep blue carrying an outsized cultural charge.
| Current Token | Edo Candidate | Notes | |
|---|---|---|---|
--bn-colour-bg |
→ | Snow White #F5F0E6 |
Warm paper background (or Washi Cream for warmer) |
--bn-colour-text |
→ | Sumi Black #1A1A1A |
Already identical — carbon ink black |
--bn-colour-muted |
→ | Storm Slate #5A7D9B |
Atmospheric grey-blue vs neutral grey |
--bn-colour-accent |
→ | Prussian Blue #1E3A5F |
Bero-ai — may need lighter tint for links |
--bn-colour-accent |
→ | Verdigris #7BA8A0 |
Alternative: distinctive, calmer, more unique |
--bn-colour-border |
→ | Sail Parchment #D4C9A8 |
Warm border (strong) — may want 50% tint |
| Sentiment colours (frustration, confidence, etc.) would need separate mapping — those are functional, not aesthetic | |||
Seen in person at the Samurai exhibition, British Museum, 1 Mar 2026. Source artworks: British Museum (1881,1210,0.260); Metropolitan Museum of Art (Kuniyoshi, Ghosts of the Taira). Hex values are approximate — sampled by eye from photographs taken at the exhibition, not measured from pigments.