Reference

How we match paint colors across brands

Paint Color HQ has 23,000+ paint colors from 14 brands and over a million pre-computed cross-brand matches. This page documents how those matches are calculated, what Delta E scores mean, and where the methodology has limits.

Short version: every color in our database has a hex code, RGB triplet, and (when available) an LRV value. To find cross-brand matches we compute the CIEDE2000 Delta E score between two colors — a perceptual color-difference standard published by the International Commission on Illumination in 2001 (CIE Publication 142) and widely used in paint, fabric, and ink manufacturing for quality control. Pairs with Delta E under 2.0 are virtually identical on a finished wall. Pairs under 5.0 are visibly similar but distinguishable. Pairs above 5.0 are visibly different.

The matching pipeline

Computing CIEDE2000 across the full database in real time would be prohibitively expensive (~250 million comparisons for a single color), so the pipeline runs offline and stores results in a cross-brand matches table.

1. RGB pre-filter. For each source color, candidates are narrowed to colors whose RGB channels fall within ±30 of the source. This Euclidean filter is cheap and runs on indexed columns; it eliminates 99%+ of the database before any Delta E math is performed.
2. LAB conversion. The pre-filtered candidates are converted from sRGB to CIE LAB color space — the perceptual color space CIEDE2000 operates on. LAB is designed so that equal distances correspond (approximately) to equal perceived differences, unlike RGB where two visually distinct colors can be numerically close.
3. CIEDE2000 calculation. The 2001 CIE formula (Luo, Cui, Rigg) computes Delta E using LAB lightness, chroma, and hue with chroma-dependent weighting. We use the standard implementation with kL=kC=kH=1, which is the default for surface coatings (paint, fabric, ink) per ISO 11664-6:2008.
4. Ranking and storage. For each source color we keep the top 50 matches per target brand, ordered by Delta E ascending. These pre-computed matches are what the color detail and match listing pages read at runtime, so the cross-brand pages serve from the cache rather than re-computing.

What Delta E thresholds mean on a wall

The plain-language verdict labels you see on color and match pages come from this table. The thresholds are calibrated against published CIE guidance for surface-coating color tolerance.

Delta E	Verdict	What you see on the wall
< 1.0	Virtually identical	Imperceptible to the human eye even side-by-side under controlled light.
1.0–2.0	Near-identical	Indistinguishable on a finished wall. A trained color professional may detect a difference under direct comparison.
2.0–5.0	Close match / Same family	Visible but small difference. Most viewers wouldn't notice unless the colors were placed next to each other.
> 5.0	Visible difference	Distinguishable side-by-side even without training. Useful as an “in the same neighborhood” reference but not as a swap.

Data sources

The 23,000+ colors in our database come from each manufacturer's published color chip data: name, color number, hex code, and (where the brand publishes it) LRV. We do not measure paint chips ourselves — the source-of-truth is whatever the brand has chosen to publish. Color names and product codes are trademarks of their respective brands.

Undertone and color-family classifications are derived from each color's LAB position relative to family centroids. The classifier sometimes diverges from a human eye on borderline colors — a famously-warm gray with LAB a* and b* close to neutral may classify as neutral rather than gray. We acknowledge this and use the brand's own family label (when set) before falling back to the classifier output.

The matches table is recomputed whenever the underlying color set changes — new brand imports, color additions, or LAB recalibrations. Match records carry no expiration date because color chip data is essentially immutable; if a brand discontinues a color we mark the row but keep the match results for historical lookup.

Known limitations

CIEDE2000 measures perceived color difference under standardized viewing conditions. Real walls don't live in standardized viewing conditions, so a Delta E match always carries caveats:

Sheen and finish. A flat and a satin in the same hex code will not look identical on a wall. Sheen affects light reflection and apparent value — we recommend matching sheen across rooms before comparing colors.
Base coat. Paint over a tinted base reads differently than paint over a pure white primer, especially for thin or transparent pigments. Most differences disappear by the second coat, but the first coat can be misleading.
Lighting. A color sampled under 2700K warm bulbs looks meaningfully different from the same color under 4000K daylight bulbs. Two colors with Delta E 0.5 under one light source can read as Delta E 3 under another. Always sample in your room's actual lighting, at multiple times of day.
Manufacturer batch variation. Published hex codes are nominal — actual mixed paint has tolerances. The CIE recommends Delta E < 1 as the acceptance threshold for production batches in coatings manufacturing, which is why we treat < 1 as “virtually identical.”
Mineral pigments and complex formulations. Brands like Farrow & Ball use mineral pigments and proprietary base structures that produce a finish character (chalky depth, color shift through the day) that can't be captured by a single hex code. A perfect Delta E match between an F&B color and a standard latex color can still look different on a wall.

The recommendation across all of these limitations is the same: always sample physically before committing to a full room, at minimum 4×4 inches, on the actual wall, viewed at multiple times of day.

Independence

Paint Color HQ is independent of every paint brand listed on the site. No brand pays for placement, ranking, or favorable mention. Color matches are derived from published data and calculated mathematically — they don't reflect editorial or commercial judgment.

The site is run by Philip Cameron, a homeowner-builder who hit the cross-brand matching problem during a personal renovation. Read more about the origin in the about page.