Banknifty future from chart above looks like making a head and shoulder formation which is in its last leg of forming the right shoulder (which it should, to become a valid pattern).  As per the chart above 19450 is tough line of resistance for bulls only once this level is sustained close basis the next up leg shall begin, till that the bank nifty is sell on rally and around 19000 there is a strong support from where it becomes a buy towards this resistance again.