The effect of laundering on the sun protection afforded by a summer weight garment

This is the authors' abstract. We don't add key points for this paper.

Aim To determine what effect a period of prolonged washing and drying of a garment would have on the photoprotection afforded by the fabric of that garment. Materials and Methods Five pure cotton T‐shirts from the same production lot were subjected to 36 consecutive standard washes. The fabric sun protection factors (SPFs) calculated from spectrophotometric UVR transmission data for samples taken from each garment after use were compared with those of control samples taken from the same garment prior to the study. Results There was a significant increase in fabric SPF after one wash in all shirts with no further change in 4 of 5 shirts after a further 35 washes. Conclusion The effect on fabric SPF of the first wash can account for most of the effect on fabric SPF of wash and wear in the use of a garment. The SPF rating of a pure cotton garment as new is valid for the standard lifetime of that garment.