What Is CIEDE2000? ΔE00 vs. ΔE*ab Explained

CIEDE2000 and ΔE00 vs. ΔE*ab

What Is CIEDE2000? ΔE00 vs. ΔE*ab Explained

In color measurement, ΔE represents the difference between two colors. However, the human eye does not perceive color differences with equal sensitivity in every region. As a result, a geometric distance in CIELAB may sometimes produce similar instrument readings for samples that look noticeably different—or different readings for samples that appear closer.

CIEDE2000, commonly written as ΔE00, was developed to address some of these perceptual non-uniformities. It remains based on CIELAB but applies corrections to lightness, chroma, and hue so that calculated differences can better correspond to visual judgments.

The key takeaway: ΔE*ab uses a relatively straightforward distance calculation, while ΔE00 applies perceptual weighting to lightness, chroma, and hue. The two formulas can return different values for the same pair of samples.

1. Why Was CIEDE2000 Developed?

CIELAB was designed so that distances in its color space would roughly correspond to perceived color differences. In practice, though, visual sensitivity is not perfectly uniform. In some chroma or hue regions, the same numerical distance does not represent the same visual difference.

Traditional ΔE*ab is intuitive and widely used, but it may not fully reflect how people distinguish colors in every region. CIEDE2000 does not create a new color space; it adjusts the way differences are calculated within the CIELAB framework.

2. What Is the Main Difference Between ΔE*ab and ΔE00?

Basic concept: ΔE*ab calculates distance in CIELAB; ΔE00 adds perceptual corrections to that distance.
Lightness: ΔE*ab uses the lightness difference directly; ΔE00 applies a lightness weighting correction.
Chroma: ΔE*ab uses the chroma difference; ΔE00 adjusts sensitivity according to the chroma region.
Hue: ΔE*ab uses a simpler calculation; ΔE00 accounts for perceptual differences across hue regions.
Tolerance: ΔE*ab is closer to a fixed-distance concept; ΔE00 can represent tolerance regions whose shape and direction vary by color region.
Use: ΔE*ab is simple and widely applied; ΔE00 can be more suitable when closer agreement with visual assessment is important.

These are different color-difference formulas. Their values should not be treated as interchangeable acceptance scales.

3. Which Color Dimensions Does CIEDE2000 Correct?

CIEDE2000 applies corrections in three dimensions:

Lightness correction: adjusts differences along L*, accounting for changes in visual sensitivity under different lightness conditions.

Chroma correction: adjusts chroma differences, recognizing that sensitivity can vary between low- and high-chroma regions.

Hue correction: adjusts hue differences and accounts for perceptual behavior in particular hue regions.

4. What Do SL, SC, and SH Mean?

CIEDE2000 uses weighting functions commonly written as SL, SC, and SH. SL adjusts the weight of lightness differences; SC adjusts the weight of chroma differences; and SH adjusts the weight of hue differences. These corrections mean that each direction in CIELAB is not assumed to have exactly the same visual sensitivity.

5. Why Is ΔE00 Often Explained with Ellipses?

If acceptable color differences are plotted in color space, tolerance regions are not necessarily circles of the same size. In some regions, people may be more sensitive to hue changes than to chroma changes. The visually acceptable region can therefore resemble a directional ellipse. This is why an elliptical tolerance region is often used to explain CIEDE2000 instead of treating every direction as an identical distance.

6. Why Can ΔE00 Differ More from ΔE*ab in High-Chroma Regions?

In high-chroma regions, sensitivity to chroma changes may not match geometric distance in CIELAB. CIEDE2000 applies chroma weighting, so the same samples can produce different values under ΔE*ab and ΔE00.

Important: ΔE00 is not simply ΔE*ab multiplied by a fixed factor. Its corrections depend on the color region and the direction of the difference.

7. Why Is the Blue Region Often Mentioned?

The development of CIEDE2000 also considered hue non-uniformity in certain blue regions. In those regions, the eye’s sensitivity to hue and chroma changes may not align with simple geometric distance in CIELAB. CIEDE2000 therefore includes an additional hue-related correction to better reflect visual perception.

8. What Are kL, kC, and kH?

The formula includes parameters kL, kC, and kH to adjust the weights for lightness, chroma, and hue differences under particular applications. Standard settings are generally used under reference conditions, while some industries or quality specifications may define different parameters.

In practice, if a customer and supplier use different kL, kC, or kH settings, their results can differ even when both report using ΔE00.

9. Can ΔE00 and ΔE*ab Be Compared Directly?

No. A customer specification of ΔE00 ≤ 1.0 is not automatically equivalent to a supplier’s ΔE*ab ≤ 1.0. The formulas differ, so the same number does not represent the same acceptance standard. State the color-difference formula clearly in any tolerance specification.

10. When Should You Consider CIEDE2000?

CIEDE2000 is worth evaluating when color decisions need closer alignment with visual assessment. Common use cases include:

Customer appearance inspection: when instrument readings need to correspond more closely to visual judgments.

High-standard color quality control: when small color differences matter or ΔE*ab often disagrees with visual inspection.

Supplier management: when consistent formulas and acceptance criteria must be established across suppliers.

R&D and color matching: when lightness, chroma, and hue differences need more detailed evaluation.

11. Which Conditions Should Be Standardized When Using ΔE00?

The formula is only one part of a comparison. When different people, companies, or instruments compare readings, also confirm:

• Instrument type and model
• Measurement aperture
• SCI/SCE mode
• Standard illuminant
• Standard observer
• Sample position and measurement method
• Color-difference formula
• Parameters such as kL, kC, and kH

Even if both parties specify ΔE00, differences in other measurement conditions can still produce different results.

CIEDE2000 FAQs

Are CIEDE2000 and ΔE00 the same thing?
Yes. ΔE00 is a common notation for the CIEDE2000 color-difference formula.

Is ΔE00 always smaller than ΔE*ab?
No. The formulas calculate differences differently, and the result depends on the samples’ lightness, chroma, and hue differences.

Does a lower ΔE00 mean the colors are closer?
Under the same formula and measurement conditions, a lower value generally indicates that two colors are closer. The acceptable limit still depends on the product, customer requirements, and quality specification.

Can ΔE*ab replace ΔE00 when a customer requires ΔE00?
It is not recommended. If a specification calls for ΔE00, use that formula and the agreed measurement conditions.

The Point of ΔE00 Is Perceptual Correction, Not Just a Newer Formula

CIEDE2000 does not replace CIELAB. It refines color-difference calculations for lightness, chroma, and hue within the existing Lab color space. When establishing color tolerances, define both the permitted ΔE and the formula and measurement conditions used.

If you are new to the basic concept of ΔE, start with our guide to what color difference ΔE means and how to interpret it.

Need help setting a ΔE00 requirement?
Share your instrument model, measurement conditions, and customer specification so we can help check whether the formula and measurement setup are aligned.

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