Basecoat Lab's color matching math works by converting digital swatches into CIE Lab, which is a numeric space built around how humans actually see color. It then calculates the distance between those coordinates. A smaller distance means the stored swatches are closer under the formula. This does not mean the physical paints were measured or that they will dry identically.
Why hex codes alone are not enough
You can record every paint swatch as a hex code, which is just a six-digit value for its red, green, and blue components. It seems logical to compare those directly, but plain RGB math is bad at tracking human vision. You can end up with a situation where two colors have a huge numeric RGB gap but look almost identical to your eye, or a tiny RGB gap that looks completely different, especially with darker shades. That mismatch is why naive color comparisons usually lead to bad matches.
What CIEDE2000 actually does
CIEDE2000 is a color-difference formula used in industries like printing and textiles. Basecoat Lab takes a stored sRGB value, converts it into CIE Lab under a D65 white point, and then calculates a distance called ΔE00 between two coordinates. A value near zero means those digital coordinates are very close. As ΔE00 goes up, the coordinates are farther apart under the perceptual model. Keep in mind that the result still inherits any errors in the original source swatches and does not measure pigment, finish, or dried paint.
From delta E to a similarity percentage
| Delta E | Display-score effect | What the site can conclude |
|---|---|---|
| 0 | 100 | The stored digital coordinates are identical |
| 1 | 95 | The stored coordinates are close |
| 2 | 90 | The stored coordinates are farther apart |
| 3 | 85 | The stored coordinates are farther apart again |
The displayed score is `100 − (5 × ΔE00)`, rounded to the nearest whole number and limited to a range of 0 to 100. This score is Basecoat Lab's own display scale. It is not a physical accuracy rate or a promise that two paints will look identical.
For example, the stored references for Citadel's Mephiston Red and Pro Acryl's Bold Pyrrole Red produce a ΔE00 of about 1.8. Under the formula, that displays as 91 percent after rounding. This makes Bold Pyrrole Red a digital candidate to test, but it does not establish a direct physical swap.
Why this catches things eyeballing misses
If you judge color by eye, you are fighting against room lighting, screen calibration, fading on printed charts, and eye fatigue after looking at too many similar colors. The calculation produces the same result every time for the same two stored values. However, that repeatability doesn't mean the source values are physically measured. The catalog uses approximate digital references, and the formula knows nothing about pigment, finish, opacity, or how the paint handles when it's wet.
How to use this when picking a match
You should use the score to rank candidates with the same finish, rather than declaring a "safe" physical swap. Check the finish type on the paint's page, then test the actual paint over your intended primer and application before you buy it for a sensitive match or a custom mixture.
FAQ
What does delta E mean in paint matching?
Delta E is a number representing the distance between two coordinates in a perceptual color space. A lower number means the stored digital colors are closer. It does not, by itself, establish that two physical paints are indistinguishable.
Why is CIEDE2000 used instead of simple RGB distance?
Plain RGB distance does not track human color perception accurately, especially in darker or more saturated colors. Using it often produces matches that look wrong in practice even when the numbers seem close.
Can the math be wrong about a match?
The math is only as good as the recorded hex color values. If the underlying color data is inaccurate, the match will be too. It also cannot account for finish, which is why you should always check the finish type separately.
Does a higher similarity percentage always mean a better paint swap?
A higher percentage means the stored digital coordinates are closer under this specific formula. It does not guarantee a better physical paint swap. Source accuracy, finish, medium, opacity, primer, and application still matter.