Flowering temperature and light strength?

Keep the lights at 100%, cannabinoids and terpenes are more important than colour. Anyway, to encourage colour change, which can not be guaranteed, the temps between day and night are the ones that matter, not just cooler day temps. To get this to happen there needs to be a 10-15 degrees Celsius difference between day (lights on) temps and night ( lights off) temps and this needs to occur for 3-4 weeks before anything happens. It only affects leaf colour too, (and is an accumalation of anthocyanins or pigments, which have no effect on potency), so once trimed there is little to even validate the experience. Flower (calyx) colour is another thing all together and is largely a function of genetics. If you want purple buds, you need to buy a strain that has the genetic dominance for doing so. Hope this helps, Organoman.