The Role of Metameric Mismatching in Colour Difference Metrics

Colour matches that are correct under factory lighting can visibly deviate under other lighting. This phenomenon, metamerism, explains why some colour specifications fail despite correct instrumental measurements. The problem arises when materials have different spectral properties but produce the same colour perception under one specific light source.

The problem extends beyond different light sources alone. When two materials have different spectral properties but happen to produce the same colour under one specific light source, an unstable situation arises. As soon as that light source changes, the spectral differences become visible as colour differences.

Limitations of conventional measurement methods

Spectrophotometers measure tristimulus values under standardised conditions. This gives a snapshot, not a prediction of behaviour under other lighting. Many colour professionals encounter samples that already show a small residual colour difference under reference conditions. This complicates metamerism assessments considerably.

Recent research shows that most correction methods fail with such “parameric sample pairs”. Empirical approaches such as additive correction produce inconsistent results. Advanced methods that work for true metamers fail completely for pure colour difference without metamerism.