Quantifying whiteness tolerance for fluorescent textiles using color-difference formulas

Area of Science:

• Textile Chemistry
• Color Science
• Materials Science

Background:

• Current whiteness indices inadequately assess fabrics treated with fluorescent whitening agents.
• A need exists for standardized methods to evaluate color differences in white textiles.

Purpose of the Study:

• To develop a reliable approach for defining industrial tolerance limits for fluorescent whitening agents.
• To combine instrumental color-difference formulas with visual assessments for accurate fabric classification.

Main Methods:

• Chemically bleached cotton fabrics were treated with two fluorescent whitening agents (Texbrite BYB, Ludox White 2B) at varying concentrations.
• Measurements included whiteness index, tint factor, and color differences (∆E*ab, ∆ECMC, ∆E94, ∆E2000).
• Pass/Fail thresholds were established based on visual acceptance rates (70%) and instrumental data.

Main Results:

• Ludox White 2B demonstrated stricter limits (ΔE94 = 0.45, ΔWI = 1.57) and a 46% higher visual acceptance rate compared to Texbrite BYB.
• Texbrite BYB exhibited wider tolerance limits (ΔE94 = 0.77, ΔWI = 4.82), but its whiteness output exceeded the CIE formula's validity range.
• A strong correlation (R² > 0.75) was found between whiteness index differences and color difference values.

Conclusions:

• Whiteness difference can serve as a practical indicator of perceived color variation in textiles.
• The study provides practical benchmarks for quality control in fluorescent-whitened textiles.
• This approach enhances the maintenance of consistent visual appearance in industrial textile applications.