The gate opens at pure black and pure white.|
But even if you're world looks pure white, if you're playing online, you'll be picking up the server world tendency which is normally "a bit white", instead of pure white
If you play offline, it might open straight away.
Play offline for a minute and check how white it is, and check the gate. If it's open, yay, if not, you'll have to shift world 1's tendency a bit more white (by killing bosses or killing invaders / black phantoms)
psn quaddy456, Dark Souls tips