You “blink” quickly back and forth between the Material Plane and the Ethereal Plane and look as though you’re winking in and out of reality at random. Blink has several effects, as follows.
Physical attacks against you have a 50% miss chance, and the Blind-Fight feat doesn’t help opponents, since you’re ethereal and not merely invisible. If the attack is capable of striking ethereal creatures, the miss chance is only 20% (for concealment).
If the attacker can see invisible creatures, the miss chance is also only 20%. (For an attacker who can both see and strike ethereal creatures, there is no miss chance.) Likewise, your own attacks have a 20% miss chance, since you sometimes go ethereal just as you are about to strike.
Any individually targeted spell has a 50% chance to fail against you while you’re blinking unless your attacker can target invisible, ethereal creatures. Your own spells have a 20% chance to activate just as you go ethereal, in which case they typically do not affect the Material Plane (but they might affect targets on the Ethereal Plane).
While blinking, you take only half damage from area attacks (but full damage from those that extend onto the Ethereal Plane). Although you are only partially visible, you are not considered invisible and targets retain their Dexterity bonus to AC against your attacks. You do receive a +2 bonus on attack rolls made against enemies that cannot see invisible creatures.
An ethereal creature is invisible, incorporeal, and capable of moving in any direction, even up or down....
This raises a few questions:
Is Glitterdust guaranteed to affect the enemy wizard? He would only take half damage from a damaging spell like Fireball, but Glitterdust doesn't inflict damage. Does the effect have a chance to miss, and if so, is it 20% or 50%?
Assuming that he is affected by Glitterdust, does it reduce the miss chance on physical attacks against him to 20%? Normally Glitterdust lets you see invisible creatures, but being ethereal is more than just being invisible. For example, an invisible creature hit by a Fireball would take full damage, whereas a wizard under the effects of Ethereal Jaunt would be unaffected, right?