What to try
- Change Requested ΔL* while watching the adjacent patches and the lightness bar.
- Add a change in Δa* or Δb* and inspect the measured ΔE76 after display conversion.
What to look for: All three axes contribute squared terms. Rounding and gamut clipping can change the requested offsets before the displayed patches are measured.
How it works
Convert both colors into the same Lab reference conditions, subtract L*, a* and b*, and take the vector length. The result combines lightness and chromatic differences. A comparison is only meaningful when both colors use the same white point and conversion assumptions.
CIEDE2000 is a different formula, not another label for the same norm. It includes corrections for lightness, chroma and hue. The experiment deliberately reports ΔE76 so its calculation can be understood and checked directly.
Use it in the Lab
Use color-distance concepts to evaluate palette reduction and gradient transitions. Pair the number with a visible comparison: a small average error can hide a locally important lost accent.
Limits & distinctions
This experiment uses sRGB input and Lab with a D65 reference. It does not calculate CIEDE2000 or certify print color tolerances.
Further reading
Delta Empfindung (ΔE) literally means "difference sensation" in German and denotes the perceived distance between two colors. While simple Euclidean distance in RGB space can measure mathematical similarity, it poorly reflects human vision because the RGB cube is not perceptually uniform. The Delta E family of formulas operates in perceptually uniform color spaces (primarily CIELAB) to produce values that correlate with what we actually see.
Evolution of ΔE Formulas
- CIE76 (ΔE*ab) — Straight Euclidean distance in L*a*b*. Simple and fast but overweights chroma differences in saturated regions.
- CIE94 (ΔE*94) — Adds weighting factors for lightness, chroma, and hue to reduce the over-sensitivity in saturated colors. Application-specific parameters for textiles vs. graphic arts.
- CIEDE2000 (ΔE₀₀) — The current gold standard. Adds rotation term for the problematic blue region, rescales the a* axis for better neutrals, and applies interactive terms between chroma and hue differences.
The Formulas
CIE76: ΔE = √((ΔL*)² + (Δa*)² + (Δb*)²) CIEDE2000 adds 5 correction terms: SL (lightness), SC (chroma), SH (hue), RT (rotation for blue), and a rescaled a* component. The full formula spans ~30 lines of code — far more complex than CIE76 but significantly more accurate.
Practical Thresholds
Industry thresholds for CIEDE2000 are roughly half those of CIE76 because the formula better accounts for how humans perceive small differences:
- ΔE₀₀ < 0.5 — Imperceptible; considered an exact match
- ΔE₀₀ 0.5–1.0 — Requires close inspection to notice
- ΔE₀₀ 1.0–2.0 — Noticeable to trained observer; acceptable for most applications
- ΔE₀₀ > 3.0 — Obvious difference; generally unacceptable in color-critical work
Use in This Platform
Our palette extraction currently uses Euclidean RGB distance (threshold 32) for grouping colors because it runs in the browser without a CIELAB conversion step. For most artwork palettes, RGB distance is sufficient — the goal is coarse grouping, not precision matching. However, Delta E becomes essential when evaluating print reproduction fidelity or comparing artwork palettes across different display profiles.
Key Takeaway
Delta E is the bridge between mathematical color distance and human perception. Where Euclidean RGB distance treats all colors equally, ΔE₀₀ respects the eye's varying sensitivity across different hue regions and lightness levels.
Related Lab categories
Sources & references
Guide updated