Tolerance Metric
The numerical distance between two color points in a specified color space indicates the degree of match between a production batch and a target standard. Textile mills calculate color difference to determine if a dyed lot falls within the acceptable range specified by the garment brand. This evaluation removes human bias from the shade matching process.
Numerical Equation
Calculated color difference is usually expressed as delta E, which represents the total error between the target and the production sample. Different mathematical models such as CMC or CIE2000 weight the lightness, chroma, and hue differences differently to match human visual perception more closely. In the CMC formula, the tolerance volume is an ellipsoid rather than a sphere, adjusting its shape depending on where the color sits in the color space.
A highly saturated red will have a larger tolerance ellipsoid than a neutral grey because the human eye is less sensitive to small changes in saturated colors.
Production Control
Mill technicians measure the color of the fabric after drying to ensure that the dye fixative has set completely. When the delta E exceeds the buyer’s limit, the fabric must be stripped of color or dyed to a darker shade. This prevents mismatched garments from reaching the retail floor.
Acceptability Border
Visual confirmation in a light booth is required even when the calculated value is low. Highly textured fabrics like corduroy or pile knits can produce anomalous spectrophotometer readings that require human override.
