Two fabrics, two paints or a paint and a printed sample can match perfectly by the window and disagree under the kitchen lights. Both reflect light differently across the spectrum, but the differences cancel out for one light and not for another. Choose a colour and see a matching pair come apart.
Solid line: sample A. Dashed line: sample B.
| Light (CIE) | CCT | A | B | ΔE00 | Result |
|---|---|---|---|---|
| Daylight, CIE D65 | 6500 K | 0.0 | Match | |
| Daylight, CIE D50 (graphic arts viewing) | 5000 K | 0.1 | Match | |
| Incandescent tungsten, CIE A | 2860 K | 0.3 | Match | |
| Cool-white fluorescent, CIE FL2 | 4240 K | 0.8 | Match | |
| Narrow-band tri-phosphor fluorescent, CIE FL11 | 4030 K | 1.8 | Slight difference | |
| Phosphor-converted white LED, CIE LED-B3 | 4110 K | 0.8 | Match | |
| Red-green-blue mixed LED, CIE LED-RGB1 | 2840 K | 2.0 | Slight difference |
Swatches show each sample as an eye fully adapted to that light would see it, so the overall warmth of the light is removed and only the mismatch between the two remains.