What is Sun-Safe color for clothing?
What’s the best way to protect yourself from the sun’s harmful ultraviolet rays (UVR), given that we need to work, travel, and sometimes play outside? Clothing is the most basic and generally the best means of sun protection. Not all clothing is equal, however, and some of it isn’t actually very good at protecting us. So, what makes a piece of clothing sun-safe?
Color Comparisons
Most of our clothing is dyed attractive or functional colors. Many dyes absorb UV, which helps reduce exposure. Darker colors tend to absorb more UV than lighter colors, including whites and pastels, but bright colors such as red can also substantially absorb UV rays. The more vivid the color, the greater the protection; a bright yellow shirt is more protective than a pale one. But even a pale fabric can offer good protection if the weave, material, weight, etc. are effective at keeping out UV. And many white fabrics have “optical whitening agents,” chemical compounds that strongly absorb UVR, especially UVA.
Fabric Factors
Of course, you can have clothing over every square inch of your body, but if the sun goes right through it, it’s not much use. Fabrics are made of tiny fibers woven or knitted together. Under a microscope, we can see lots of spaces between the fibers; UV can pass directly through these holes to reach the skin. The tighter the knit or weave, the smaller the holes and the less UV can get through. Twill, used to make tweeds or denim, is an example of a tightly woven fabric. Open weave fabrics provide much less protection.
Fabrics can be made from many types of fibers, including cotton, wool, and nylon. Most fibers naturally absorb some UV radiation, and some have elastic threads that pull the fibers tightly together, reducing the spaces between the holes. Synthetic fibers such as polyester, lycra, nylon, and acrylic are more protective than bleached cottons, and shiny or lustrous semi-synthetic fabrics like rayon reflect more UV than do matte ones, such as linen, which tend to absorb rather than reflect UV. Finally, consider the fabric’s weight and density — light, sheer silk gauze will provide far less UV protection than heavy cotton denim.
Source: Skin Caner Foundation