Negative Energy Protection

[Ethdred]

Reading the Manual of the Planes, I note there are places that give off a constant 1d6 negative energy damage. The only spells I can find that protect from negative energy are limited in duration - is there any way of protecting a party from this damage long enough for them to do a full adventure on such a plane? Or should I just turn them all into wraiths now and have done with it? :)

[Flickerdart]

Tomb Tainted Soul would heal the party instead of harming it, so you could just have a ritual that temporarily tomb-taints them.

[Malimar]

Ring of Negative Protection from the Magic Item Compendium: 36,000gp, "You can ignore the 1d6 points of damage dealt by negative-dominant planes, such as the Negative Energy Plane, each round. You also cannot gain negative levels."