Dampen Magic

Dampen Magic is a mage utility buff. The opposite of Amplify Magic, it decreases the amount of damage the target takes from each enemy spell, but also decreases the healing a target group member takes from each healing spell.

Damage taken and healing taken is the same effect as the spell power stat found on some gear. For example, a warlock casting a damage spell on a target buffed with Dampen Magic rank 6 will have the same effect as if he had 120 less +damage on his gear.

Tips and Tactics
Many players don't realize that, in certain situations, Dampen Magic is one of the mage's best defensive buffs. It reduces the damage caused by many kinds of non-physical attacks, not only traditional spells. This includes natural attacks like poison, DoT effects of diseases and curses, acid, and even melee attacks by fire, frost and wind elementals.

Most mages use this spell when soloing or in small groups with no healer to lessen the damage enemy casters dish out. Most enemy damage spells are bolts with long casting times; you'll really see the effect when 100 damage becomes 60.

Like Amplify Magic, this spell has benefits and drawbacks and it is important to choose the correct spell. This spell can be very dangerous if used incorrectly, cutting the healing team's spell power and preventing heals from being effective. Dampen Magic is useful in group situations where players will take very many magical damage hits. In these situations, it will prevent a large amount of damage, allowing the healing team more time to react, and allowing all players more time to get move out of avoidable damage.

When deciding whether or not to use this buff, consider the number of damaging spells likely to hit vs. the number of heals. In raid situations, when a tank has multiple healers on him at a time and will get many more heals per second than damaging spells per second, the net healing decrease will be greater than the net damage decrease. Even when fighting most magic-damage bosses, Amplify Magic is still often more beneficial on the tank than no buff or Dampen Magic would be.

When to use Dampen Magic: On a fight with a steady stream of magic damage, such as the Twin Val'kyr or Sapphiron encounters, always have your mage(s) cast Dampen Magic on the entire raid; it will vastly reduce damage taken, making healing much easier. Usually beneficial on the DPS and Healers. Don't use Dampen Magic if there are relatively few magic damage hits, or if there is a good reason to use Amplify Magic.

When to use Amplify Magic: When fighting a boss such as Deathbringer Saurfang or Gruul the Dragonkiller, where only physical damage is taken, always have your mage(s) cast Amplify Magic on the entire raid; it will increase all healing done, making healing much easier. Usually beneficial on the Tanks. Don't use Amplify Magic if it presents a danger of tanks being one-shot, or if there is a good reason to use Dampen Magic.

When to use neither spell: While many will claim that it's often best to use neither buff, this is actually untrue, and very rarely will there come a time when it is optimal for any player to have neither buff active. This is easy to see, because removing one buff is the exact same effect as applying the other, and if it was beneficial to do one, then it must follow that is beneficial to do the other, which is almost always true. However, if you risk picking incorrectly and using the wrong buff, it may be "safer" to run without either.