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.
Parametric Factor Kc
Chroma Tolerance Adjustment
Mathematical weighting in color difference equations allows for the modification of the acceptable deviation in saturation levels for a dyed material. The parametric factor kc is primarily used within the CMC (l:c) formula to adjust the sensitivity of the pass and fail calculation to the chromaticity of the sample. In most commercial textile applications, this value is set to one.
This default setting assumes that the standard observer is equally sensitive to changes in chroma and hue.
Calculated Sensitivity
Changes to this variable influence the shape of the elliptical tolerance volume in the color space. When the parametric factor kc is increased, the tolerance for variation in the vividness or the purity of the color becomes wider. This adjustment is sometimes necessary for specific fabric types or finishes where high saturation is difficult to maintain consistently.
Formula Application
Standard laboratory software includes this parameter as a configurable setting for automated color grading. The choice of the parametric factor kc depends on the end use of the product and the specific agreement between the buyer and the manufacturer. It works in conjunction with other factors to ensure that the numerical delta e value corresponds to what a human inspector sees.
Commercial Impact
Correct setting of the factors ensures that minor variations that are invisible to the eye do not cause the unnecessary rejection of a production lot. Conversely, a setting that is too loose might allow visible differences in color intensity to pass through the inspection process. The parametric factor kc provides the flexibility needed to handle different color palettes and textile textures.