The longer they are exposed to sunlight, the lighter they will become. After remain in sunlight for two weeks their complexion will blend in like the rest.
It's actually a bit of both of the above answers... yep - you are green until you have been here for two whole weeks (which seems to last an eternity at the time) but it also means that us grey 'uns can spot you green 'uns a mile off and simply admire your fresh, young looking complexion... Hehe, we are also liable to tease said young green 'uns a bit.....