Discussion
The SPF (sun protection factor) is a multiplier of the time it takes your skin to burn in unprotected circumstances.
SPF=0 is the same as no protection; SPF=30 means you can stay out 30 times longer than with no protection.
The time to burn part obviously varies. It could be as quick as 15 minutes for your skin to start smouldering, without protection, on some sunny beach. Or if you whip your top off today and start sunbathing, it'll be hours, if you get any effect at all. The longer you stay in the sun beyond the level of protection that your sunscreen gives you, you will burn. If you reapply that sunscreen to top up or extend that amount of time you stay in the sun, you will still burn.
Incidentally, most people don't put on anything like enough to actually protect themselves. It's not uncommon to put a smattering of (say) SPF 30 on that is actually the equivalent of SPF3 protection. Speaking as someone who was hospitalised with sunstroke...
SPF=0 is the same as no protection; SPF=30 means you can stay out 30 times longer than with no protection.
The time to burn part obviously varies. It could be as quick as 15 minutes for your skin to start smouldering, without protection, on some sunny beach. Or if you whip your top off today and start sunbathing, it'll be hours, if you get any effect at all. The longer you stay in the sun beyond the level of protection that your sunscreen gives you, you will burn. If you reapply that sunscreen to top up or extend that amount of time you stay in the sun, you will still burn.
Incidentally, most people don't put on anything like enough to actually protect themselves. It's not uncommon to put a smattering of (say) SPF 30 on that is actually the equivalent of SPF3 protection. Speaking as someone who was hospitalised with sunstroke...
anonymous said:
[redacted]
Your skin sees less UV, so will tan slower. However, as your body is only able to produce so much melanin in any time period. Once you have reached your maximum level of production / day you will not see a signifigant increase from toasting your self further.
As most people probably go for the max rate irrespective of suncream, you appear to "tan at the same rate, the higher the factor just means you can stay out longer before you burn".
z
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