Color Fastness

Color fastness measures how well a fabric retains its color when subjected to various conditions that might cause fading, bleeding, or transfer. This specification is critical for ensuring products maintain their appearance throughout their useful life, and it's tested against multiple exposure types since a fabric might perform well against washing but poorly against light, or vice versa.

The textile industry uses standardized ISO tests to evaluate different aspects of color fastness, each simulating specific real-world conditions:

Results are reported on a standardized 1-5 scale. Grade 5 indicates excellent fastness with no visible change, while Grade 1 indicates severe color change or transfer. Intermediate grades represent slight (4), noticeable (3), and considerable (2) changes. Testing uses standardized gray scales for objective comparison.

Different applications require different fastness levels. Bedding should achieve Grade 4 or higher for both washing and light fastness, since sheets undergo frequent laundering and may be exposed to sunlight. Apparel typically requires Grade 4+ for washing and Grade 3+ for rubbing, as garments experience significant friction during wear. Outdoor fabrics demand Grade 5+ for light fastness to withstand prolonged sun exposure.

The dyeing method significantly affects color fastness. Solid-dyed fabrics, where color penetrates the entire fiber, generally show better fastness than surface-printed fabrics. Disperse printing on polyester achieves excellent fastness because the dye bonds at the molecular level. Digital printing technology has improved dramatically, with modern pigment inks approaching the fastness levels of traditional dyeing methods.