Abstract

This study investigates the impact of repeated laundering up to 50 cycles on the color spectrum of naturally colored cotton fabrics for apparel. It aims to understand how laundering affects color lightness and intensity, addressing a gap in prior studies that often tested only a few laundry cycles and lacked detailed color metrics. The study also assesses whether color changes in naturally colored cotton meet ASTM standard requirements for acceptable color retention in clothing. Two naturally colored cotton jersey knit fabrics in the same light brown (Vicuña) shade, but different weights were tested. AATCC standard test methods were followed. The fabrics were washed and dried on “normal” settings. Color was measured at multiple intervals (0, 1, 5, 10, 20, 30, 40, 50 cycles) by a spectrophotometer for L* (lightness), a* (redness), and b* (yellowness) values. Color difference (ΔE) was calculated, and visual assessments were conducted with the AATCC Gray Scale by three assessors under controlled lighting. This study quantified these changes using statistical analysis and revealed that color change significantly increased as the number of laundry cycles increased. The two fabrics in different weights exhibited similar color retention characteristics. Initially, the fabrics darkened slightly after 1 to 10 cycles, then became significantly lighter after 20 cycles, with further lightening observed after 50 cycles. Using the AATCC Gray Scale, evaluators detected significant darkening after 5 cycles and further lightening after 20 cycles, with no significant changes beyond 30 cycles. The color intensity of both redness and yellowness significantly weakened with more laundry cycles, particularly after 20 cycles for redness and progressively across multiple cycles for yellowness. The results confirm that naturally colored cotton is a great choice for apparel products because of its ability to meet the ASTM standard requirement for acceptable color retention after repeated laundering up to 50 cycles.

Keywords:Naturally Colored Cotton; Color; Repeated Laundering; Color Lightness, Color Intensity