How does Duchess blue (No.20 C 40) by BS 4800 compare with Dulux’s closest paints? The nearest match by perceptual distance is Dulux Sapphire Splendor (ΔE 3.5, “very close”). 1 more Dulux colour sit within ΔE 4 — close enough that the difference is hard to spot once paint’s on the wall. These 2 Dulux paints are all priced at £10.20 per litre.
BS 4800 Duchess blue vs Dulux
2 closest Dulux matches ranked by ΔE
ΔE (CIEDE2000) is a perceptual distance metric — lower means a closer match. Matches under ΔE 2 are typically indistinguishable; ΔE 2–4 looks “the same” once dry on a wall; ΔE 4–6 is noticeable side-by-side. Always view a sample pot before committing — screen colours and lighting vary.
| Colour | Number | ΔE | Match quality | Price/L | Price/m2 |
|---|---|---|---|---|---|
| Sapphire Splendor | — | 3.5 | very close | £10.20 | £1.57 |
| Sapphire Splendour | — | 3.5 | very close | £10.20 | £1.57 |