The sun’s visible rays are the ones in the colour spectre – from shorter wave indigo rays to red rays with longer wavelengths. But it is the invisible ultraviolet sunrays that are especially dangerous.
How sunrays damage your skin
If you go into the sun unprotected in any way, UV rays immediately penetrate your skin - this is what happens.
Which SPF should you use?
Sunscreens block or absorb ultraviolet light, but they must be chosen and applied correctly. To understand them properly you need to know what the term SPF stands for and what it means.