Cool finish
Running the dark period colder through the last days of flower to push anthocyanin expression, at a cost in yield and an increase in bud rot risk.
Cooler nights move pigment in cultivars that carry the genetics for it. The trade is real: the same cold night slows ripening, and every night temperature cold enough to move color sits inside the window botrytis prefers, 63 to 75 °F (17 to 24 °C).
That makes a cool finish a humidity decision as much as a temperature one. You cannot leave the botrytis window by going colder, only by running drier, so the dew point has to come down with the room.