The Yellowing Test is a method used to evaluate the resistance of fabrics or textile products to yellowing caused by various environmental factors such as temperature, light, air pollution, chemicals, or storage conditions.

Phenolic Yellowing in garments occurs when certain conditions are present while fabrics or garments are being stored.

These are an alkaline finishing, nitrogen dioxide present in the air, and the presence of phenols, this is often from storage in polyethylene bags or film containing butylated hydroxyl toluene or similar compounds.