Originally Posted by Utah12
Thanks Andrew, when you say swirl marks are caused by UV rays I was surprised. I always attributed the circular swirls to sponge use, incorrect towels etc. What is the mechanism in which UV light causes these swirls?
~ all of the factors you listed are causes of swirls but when doing so in the sunlight things are made to be much worse and more enhanced...
an example... have you ever clean windows in the direct sunlight... streak central... no sun... no streaks...
i'm not sure as far as a technical reasoning for way the uv rays attribute but... the proof is there.