Washington, Oct 15: Wear blue or red, instead of yellow, if you wish to protect yourself from harmful ultraviolet (UV) rays.

Scientists in Spain are reported to have said that the same cotton fabric dyed deep blue or red provide greater UV protection compared to yellowish hues. Their study could lead to fabrics with better protection against the sun.

Ascension Riva of the Universidad Politecnica de Cataluna, Spain and colleagues explained that colour was one of the most important factors in determining how well clothing protects against UV radiation.

Gaps, however, exist in scientific knowledge about exactly how colour interacts with other factors to influence a fabric's ability to block ultraviolet protection factor (UPF).

The scientists describe the use of computer models that relate the level of UV protection achieved with three fabric dyes to their effect in changing the UPF of fabrics and other factors. In doing so, they dyed cotton fabrics in a wide range of red, blue and yellow shades and measured the ability of each coloured sample to absorb UV light.

Fabrics with darker or more intense colours tended to have better UV absorption. Deep blue shades offered the highest absorption, while yellow shades offered the least.

Clothing manufacturers could use information from this study to better design sun-protective clothing, the scientists indicate, says a release of the American Chemical Society (ACS).

These findings are slated for publication in the November issue of ACS Industrial & Engineering Chemistry Research. (IANS)