Quantifying Spectral Metamerism and CIEDE2000 Tolerance Limits in Multi-Component Garment Assembly Lines
CIEDE2000 tolerances below 0.8 dE00 prevent visual metameric mismatches between garment shells and trims under D65 and retail LED illuminants.
Spectral Metamerism
Optical Property
Physical conditions allow two distinct material samples to appear identical under one light source while showing a mismatch under another. Appearance of spectral metamerism happens because the reflectance curves of the two samples cross at least three times in the visible spectrum. This allows the human eye to perceive them as the same color under specific lighting.
Visual Checkpoint
Quality control teams use light boxes to check fabric matches against a master standard under daylight and fluorescent bulbs. Detecting spectral metamerism is a critical step before a mill ships bulk fabric to a garment factory. If the match fails under one light, the customer may see different colors on the same garment.
Reflectance Curve
Spectrophotometers plot the percentage of light reflected at every wavelength to identify potential mismatches. Even when samples look the same to a person, spectral metamerism is revealed by the divergent paths on the graph. This tool allows for the selection of dye combinations that behave similarly across the whole spectrum.
Evaluation Range
Consistency is only guaranteed for the specific light sources used during the verification. Avoiding spectral metamerism requires using the same dye classes and chemical recipes for both the standard and the production batch.