Blacklight vs. Detect Magic

[TheGemini]

If this has already been fully explored here, please forgive me:

Blacklight (from FRC): "You create an area of total darkness. The darkness is impenetrable to normal vision and darkvision..."

Detect Magic (from PHB): "3rd round [of concentration]: The strength and location of each [magical] aura. If the items or creatures bearing the auras are in line of sight, you can make Spellcraft skill checks to determine the school of magic involved in each......Magical area, multiple types of magic, or strong local magical emanations may distort or conceal weaker auras."

The situation: The evil wizard is in a laboratory, behind a secret door of his bedroom. He has "Alarm(ed)" the bedroom so that he will be alerted when the party enters it. If he hears them approach the secrect door, he will immediately cast Blacklight on himself. The entrance and majority of the secret lab will be filled with inky blackness. In the room will be the evil Wizard wearing his Cloak of Intelligence (+4), and several potions on a table at the other end of the room.

The thief opens the secret door and the party's sorceror approaches the doorway. Let's assume he is allowed 3 rounds to Detect Magic. What does he sense? I can make several arguments, but I could really use some advanced rules insight to pick among them.

 

[Thanee]

Detect Magic - without having line of sight - detects strength and location of every magical aura within line of effect (plus those behind not too thick wood/stone, see spell description for details).

But you cannot discern the schools of the auras, unless you can actually see them.

This is what the character would sense (IMHO):

A 20 ft. circular area is covered by a faint aura (Blacklight). Depending on where the Sorcerer is (outside of the darkness area, but having it in sight), even the school (Evocation) could be discovered.

On square X (wizard position), somewhere in the center of the other magical area, there is a moderate aura (the cloak).

On square Y (potion table position), there are <number of potions> additional magical auras of various strengths (the potions).

Bye
Thanee

 

[werk]

I question the feasibility of this argument because I think that the blacklight's caster can see through the darkness yes?

I would DM it such that the detect magic caster sees only the area of magical darkness (caster does not have line-of-sight with anything inside the darkness). It is an active spell and basically is making too much noise to see anything inside the darkness...consider it magical fog.

Same with a chest with Glyph of Warding on it. Can't see inside the chest using detect magic because the overriding spell.

Detect magic is a cantrip, I'd let pretty much anything best it.