Colour Measurement and Colorimetry of Polyester
topic
Colour measurement of dyed polyester fabric: reflectance spectrophotometry (D65 illuminant, 10° observer, 0°/45° or d/8° geometry per ISO 13655). CIE L*a*b* colour space: L* (lightness 0–100), a* (red–green), b* (yellow–blue). Colour difference ΔE*₀₀ (CIEDE2000 formula — perceptually uniform). Metamerism index (MI): colour match under D65 but mismatch under A illuminant (tungsten) — caused by different dye combinations with same colour point under reference illuminant. Kubelka–Munk theory (K/S values) relates reflectance to dye concentration.
Role
Colorimetry and spectrophotometry are fundamental tools for polyester quality control and process development. Understanding CIE colour spaces, CIEDE2000 colour difference, and Kubelka–Munk K/S values is essential in textile dyeing and coloration science.