Thanks CHB and High,
r1tony,
just make sure you get the right genetics, some of them are piss poor and don't turn purple, this is where you hear tons of guys trying to shock their plants into purpling with all sorts of garbage or lowering temp techniques.
I was fortunate enough to get a 80% dark strain with good yield.
When you crack my buds open it;s purple to the core! some purple strains affect only the outside.
** There is no special trick to getting bud frosty, just keep your humidity low & don't bother them.**
Here is a picture of it at day 29.
Most good purple strains show purple tips around 30 days and turns dark when ripening.