LAB to Pantone Converter
Enter a CIELAB color — L (lightness 0–100), a (green–red axis −128 to 127), b (blue–yellow axis −128 to 127) — to find the closest Pantone Solid Coated match. Matching uses Delta E 2000 in LAB space, which is exactly what the CIE metric was designed for: LAB is the only widely-used color space where numerical distance corresponds to perceived difference, so Pantone matching is most accurate there. Top eight matches are ranked by similarity.
What is LAB to Pantone conversion?
CIELAB (also written L*a*b*) is a color space the CIE defined in 1976 specifically to be perceptually uniform. In LAB, a numerical distance of 10 units corresponds to roughly the same perceived difference regardless of where in the space you are — which is not true of RGB. That property makes LAB the natural choice for color matching, and it is why Delta E 2000 (which operates on LAB values) is the industry-standard metric for perceptual color difference.
Pantone is a print specification system. Its 2,371 Solid Coated colors are physical ink mixes, and no LAB value maps exactly to any of them. This tool converts LAB to RGB (clipping to sRGB gamut if needed), then finds the closest Pantone match using Delta E 2000. The conversion is a chain of approximations, but it is the same chain that professional color-management software uses — and it is more principled than naive RGB matching because the color distance is measured in a perceptually uniform space.
Understanding the a* and b* axes
The hardest part of LAB for most designers is the two chromatic axes. Here is the mental model:
- L* (lightness) — 0 is pure black, 100 is pure white, 50 is mid-grey. This one is intuitive.
- a* (green ↔ red) — negative values are green, positive values are red. a* = 0 means the color is neutral on this axis (no red or green bias).
- b* (blue ↔ yellow) — negative values are blue, positive values are yellow. b* = 0 means the color is neutral on this axis (no blue or yellow bias).
| Color | L* | a* | b* |
|---|---|---|---|
| Pure white | 100 | 0 | 0 |
| Pure black | 0 | 0 | 0 |
| Mid grey | 50 | 0 | 0 |
| Pure red (sRGB) | 53 | 80 | 67 |
| Pure green (sRGB) | 88 | −79 | 81 |
| Pure blue (sRGB) | 32 | 79 | −108 |
| Yellow (sRGB) | 97 | −22 | 95 |
| Cyan (sRGB) | 91 | −48 | −14 |
| Magenta (sRGB) | 60 | 98 | −61 |
Note that pure red, green, and blue are not at the axis endpoints — sRGB's primaries are placed by display technology, not by LAB's perceptual design. That is why a color that "looks like pure red" to a designer might be `L=53, a=80, b=67` rather than `L=50, a=100, b=0`. Also note that yellow has a very high L* (97) — yellow is the brightest color in sRGB, which is why the formula `L*` can be surprising: a pure-looking yellow is almost white in LAB's lightness.
How the conversion works
The conversion runs in four stages. First, LAB converts to XYZ using the standard CIE formula (with D65 white point). Second, XYZ converts to linear sRGB. Third, linear sRGB applies the sRGB gamma curve to get display RGB, and any out-of-gamut channels are clipped to 0–255. Fourth, the resulting RGB is compared against each Pantone color's LAB using Delta E 2000, and the top eight are returned.
The gamut clipping in step 3 is where approximations arise. LAB can represent colors that sRGB screens cannot display — for example, very saturated cyans and very deep magentas. When you enter such a LAB value, the RGB conversion clips to the nearest displayable color, and the Pantone match is against that clipped color, not the original LAB. For colors well inside the sRGB gamut (which includes most Pantone-approximable colors), clipping does not occur and the match is only limited by Pantone's own 2,371-color granularity.
Accuracy and limitations
- Gamut clipping. LAB values outside the sRGB gamut are clipped to the nearest displayable color before matching. If you enter an out-of-gamut LAB value, the result is a Pantone match for the clipped color, not the original LAB.
- Screen vs print. LAB describes a color abstractly; Pantone describes an ink. Even a Delta E 0 match on screen will look different on paper because screens emit light and paper reflects it.
- Pantone library scope. This tool matches against the Solid Coated (C) library only. Other Pantone libraries (Uncoated, TCX, TPG) are not consulted.
- D50 vs D65. Many color-management systems use D50 white point for print work, while we use D65 (standard for sRGB). Values will differ slightly between D50-based and D65-based LAB.
Use cases
- Color management. LAB is the interchange space in ICC workflows — converting from LAB to Pantone is a standard step when translating a color-managed PDF to a Pantone-based print spec.
- Perceptual color matching. When matching a measured LAB value (from a spectrophotometer) to a Pantone code, LAB is the space you work in because it is perceptually uniform.
- Print color accuracy. Matching proof colors or Pantone library colors requires working in LAB because RGB distance does not correspond to perceived difference.
- Brand color maintenance. Verifying that a printed color matches a brand Pantone involves measuring LAB and computing Delta E — which is what this tool previews.
Common mistakes
- Assuming a* = 0, b* = 0 means "black" — it means "neutral mid-grey at whatever L* you specified". Black is specifically L* = 0.
- Confusing a* with "red amount" only — a* measures green vs red, so a* = −40 is green, not "less red".
- Entering LAB values from a D50-based color-management system and comparing to our D65-based matches — values will shift.
- Entering very saturated LAB values and expecting the Pantone match to reflect the original LAB — it reflects the clipped sRGB color.
- Using Delta E 76 comparisons (which this tool does not do) — Delta E 76 ignores perceptual non-uniformities and produces misleading matches, which is why Delta E 2000 is the standard.
LAB vs RGB vs HSL
| Attribute | LAB | RGB | HSL |
|---|---|---|---|
| Device-dependent | No | Yes (sRGB) | Yes (sRGB) |
| Perceptually uniform | Yes | No | No |
| Used for | Color matching | Display, print, code | CSS, design tools |
| CSS-native | No (lab() in modern CSS, rare) | Yes — rgb() | Yes — hsl() |
| Best for | Pantone/print matching | General display | Web colors, palettes |
Frequently asked questions
How do I convert LAB to Pantone?
Enter L (0–100, lightness), a (−128 to 127, green–red axis), and b (−128 to 127, blue–yellow axis). The converter converts the LAB value to RGB (clamping out-of-gamut values to the sRGB gamut), then finds the closest Pantone Solid Coated match using Delta E 2000. The top eight matches are ranked by lowest Delta E, so the first row is the closest match.
What is CIELAB?
CIELAB (also written L*a*b* or LAB) is a color space defined by the International Commission on Illumination (CIE) in 1976. It was designed to be perceptually uniform — meaning a given numerical distance in LAB should correspond roughly to the same perceived difference regardless of where in the space you are. L* is lightness (0 = black, 100 = white), a* is the green–red axis (−128 green to +127 red), and b* is the blue–yellow axis (−128 blue to +127 yellow). Unlike RGB, LAB is not tied to a specific device, which is why it is used as the interchange space for color matching.
Why use LAB instead of RGB for color matching?
Because LAB is perceptually uniform and RGB is not. In RGB, the distance between (255, 0, 0) and (200, 0, 0) is 55, and the distance between (0, 255, 0) and (0, 200, 0) is also 55 — but the human eye perceives those two differences very differently. In LAB, the same numerical distance corresponds to approximately the same perceived difference everywhere. This is why Delta E 2000 (which operates in LAB) is the industry standard for color matching, and why Pantone matching is done in LAB rather than RGB.
What do a and b values mean in plain terms?
a* measures how green vs how red a color is: negative a* is green, positive a* is red, and a* ≈ 0 means the color is neutral on that axis. b* measures how blue vs how yellow a color is: negative b* is blue, positive b* is yellow, and b* ≈ 0 means the color is neutral on that axis. So L=50, a=0, b=0 is a mid-grey; L=50, a=60, b=0 is a mid-red; L=50, a=0, b=-60 is a mid-blue; L=50, a=-60, b=0 is a mid-green.
Is LAB to Pantone conversion exact?
No. LAB describes a color independent of any device, but Pantone describes a physical ink mix. Converting LAB to Pantone requires (a) converting LAB to sRGB (which may clip out-of-gamut LAB values), then (b) finding the nearest Pantone in that RGB space using Delta E 2000. Both steps involve approximation. The result is a visual approximation, not an exact physical match.
What is the range of valid LAB values?
L ranges from 0 (black) to 100 (white). a and b are technically unbounded, but in practice for sRGB colors: a* is typically between −128 and 127, and b* is typically between −128 and 127. Most real colors fall in a narrower range: a* between −60 and 80, b* between −80 and 100. Values outside these ranges may produce colors that cannot be displayed on a standard sRGB screen.