Delta E and CIELAB: The Color Science Behind Dialed GG's Scoring
Most color-matching games compare your guess to the target in RGB. They subtract the red channels, the green channels, the blue channels, and call that the "distance." It's fast, it's simple, and it's wrong.
Dialed GG doesn't do that. It converts both colors into CIELAB and measures Delta E, the same metric Pantone uses to certify whether your brand color really is your brand color. Here's what that means and why it matters for how you play.
The Problem With RGB Distance
RGB is built for screens, not eyes. A 10-point shift in the green channel of a saturated red is barely visible. The same 10-point shift in a near-gray makes the color look meaningfully different. RGB treats both as identical "distance 10," which is why RGB-based games punish you for the same numeric error regardless of how perceptually wrong it actually is.
What we really want is a color space where equal numeric distance equals equal perceptual difference. That's the design goal of CIELAB.
What CIELAB Actually Is
CIELAB (also written CIE L*a*b*) describes color with three values:
- L* — lightness, 0 (black) to 100 (white).
- a* — green to red axis (negative is green, positive is red).
- b* — blue to yellow axis (negative is blue, positive is yellow).
The key property: CIELAB was designed in 1976 to be perceptually uniform. A move of 1 unit in any direction is supposed to look like the same amount of color difference to a human observer, anywhere in the space. It's not perfect — it's a little off for blues and very saturated colors — but it's vastly closer to human vision than RGB.
Delta E: The Distance Metric
Delta E (often written ΔE) is the distance between two colors in CIELAB. The original 1976 version is just Euclidean distance: square root of the squared differences in L*, a*, and b*.
What matters is how the numbers map to what you can actually see:
| ΔE | Perceptual meaning |
|---|---|
| ≤ 1.0 | Not perceptible by most people. The "just noticeable difference" threshold. |
| 1.0 – 2.0 | A minor difference, visible only to a trained eye. |
| 2.0 – 3.5 | Noticeable. Often the limit for commercial color matching. |
| 3.5 – 5.0 | Clear difference. |
| > 5.0 | Obviously different colors. |
The print industry, paint manufacturers, and the entire Pantone matching system live and die on these thresholds. When a brand says "my logo must match within Delta E 2," they mean the color has to be within that small radius in CIELAB space — anywhere else and a customer would notice.
CIEDE2000: The Modern Refinement
The original 1976 Delta E has a known weakness: it overestimates differences in the blue region and around neutrals. To fix this, the CIE released CIEDE2000 — a weighted version that corrects for these perceptual quirks.
Most professional color tools today use CIEDE2000. It's slightly more forgiving in the blues, slightly more strict near gray, and overall closer to what your eye reports.
What This Means for How You Play Dialed GG
Once you know the math, Dialed GG's scoring stops feeling arbitrary. A few practical consequences:
- Getting the hue family right matters most. Confusing a red for an orange will cost you a lot more than landing slightly off on saturation within the right hue.
- A vivid wrong color is punished harder than a slightly-off neutral. Saturated misses move you far in CIELAB; muted misses don't.
- Brightness errors near black or white are forgiving. Near 0% or 100% L*, perceptual distance compresses — you can't really tell a 5% black from a 7% black.
- The hardest colors to get right are mid-saturation mid-brightness. That's where CIELAB has maximum resolving power, and where your eye does too.
The Bigger Picture
Color perception isn't linear. RGB pretends it is, and that's why RGB-based color games feel unfair when you "almost" got it right. CIELAB and Delta E exist because the people who really care about color — print engineers, paint chemists, brand managers — needed a number that matches what humans actually see.
Dialed GG uses the professional metric so that your score reflects your eye, not your arithmetic. If you want to see this in action, play a round of Dialed GG and watch how the score reacts when you're "close in hue but wrong in saturation" vs. "right in saturation but wrong in hue." The asymmetry is the whole point.
Sources & further reading