Building a Complex trap

[Lupine]

So, as the title says, I'm building a complex trap centered around light as a trigger / resolve feature. The idea is that the trap was built by a pair shadow magic sorcerors, who use their darkness feature to open a brass door, which presumably no one else would be able to (although anyone with darkvision could do it)

I would like some non-resourced way to have a bright light source in the room, to shut down the darkivsion appraoch. So, while a torch would provide the light, it wouldn't be the solution, because the trap requires darkness to function. The obvious solution is for a continual flame, but that's kinda lame, and also isn't available to sorcs. So, what other ways can this lighting be done by sorcs. If no other listed way, are there any parts of the trap you think would work well for this, while still giving ligh?
Below is linked the trap, if anyone wants to steal it or give advice. It's targetted for around level 5, but I wasn't tightly regulating the DCs or damage.
After the temporary sealing of the Shadowfell crossing by the Frostmire centaurs, this trap was created by a pair of Shadow Magic Sorcerers to protect the portal’s integrity. It blocks the entrance to the hallway with a stone iris, which opens when the trap is resolved. The room before the iris is round, and relatively sparse.
In the center of the room is a hexagonal fountain. The top of the fountain has a small recess, which has a sharp spike in the center. From three sides of the spire, there are bat-winged shapes which point down to the fountain’s bowl. A creature can choose to attempt a blood sacrifice to the fountain. To do so, they have to press their hand down into the spike, which draws the creature’s life force from their hand. The creature must make a DC13 constitution saving throw. On a failure, the creature takes 1d4 necrotic damage. On a success, the sacrifice takes, and no damage is taken.
Above the fountain is a strange clockwork device, which whirs and ticks irregularly. It appears to be somewhat arrow shaped, and pointing towards the iris.
The room is illuminated with bright light by a pair of continual flame torches.
Bypass
The trap can be bypassed if a blood sacrifice to the fountain while in darkness. The blood then spells out a word, which must be spoken for the iris to open.
Trigger
The trap is triggered when a spell is expended when a blood sacrifice is given in dim or bright light.
Ending the trap
The trap ends, and the iris opens if, at any point, a blood sacrifice is made while not in dim or bright light. The effects of the noxious fountain also cease immediately if the trap ends.
Active Elements
Deadly Gas (Initiative 10)
The radius of the Noxious Fountain’s effect increases by 5 feet.
Dynamic Elements
Arcane Windmill
Understanding the machine takes intelligence (arcana) checks, with it being a DC15 to understand what the machine is measuring, and DC20 to be able to understand the measurements themselves. It is measuring the strength and direction of flux in the weave. In effect, it is a windmill for magic. To take these measurements, the Arcane Windmill stores energy.
The Sorcerers have rigged the device so that any creature that steps within 5 feet of the Noxious Fountain gets blasted with a bolt of magic energy. The creature does not get blasted if the device cannot see the creature. The creature must make a DC15 Intelligence saving throw taking full damage on a failure, or half on a success.
The blast deals two damage dice of force damage, starting at 2d12. When it fires, the dice type lowers, so 2d12 turns to 2d10, and so on. Additionally, at initiative 20, roll a d4. On a 1, the dice type of the damage increases.
The Arcane Windmill’s damage part can be disabled safely. Alternatively, the windmill itself can be destroyed. It has AC 20, and 8hp. If it is destroyed, it creates a blast of arcane power. All creatures within 10 feet of the Arcane Windmill must make a DC15 intelligence saving throw. On a failure, the creature takes 2d12 force damage and is knocked prone. On a success, the creature heals that much damage.
Constant Elements
Noxious Fountain
This seemingly dry fountain turns the sacrificed blood into a toxic cloud when the trap is triggered. When a creature starts its turn in the cloud or enters it during its turn, must make a DC11 constitution saving throw, or take 6d6 poison damage. A creature which holds its breath makes this check with advantage.
The Noxious fountain has three ports from which the toxic gas emanates from. Each one can be disabled with a DC of 13

[Man_Over_Game]

Darkvision makes things appear in black and white, right?

So have a puzzle that uses a plethora of colors and lines that don't make any sense. In order to make sense of the patterns, you need to see it with Darkvision, which then removes the unnecessary colors and blends the important ones to make something that's coherent and reveals the pattern.

Have the place be lit up with mirrors, so that folks entering the area think of them as a convenience (when they're actually creating the puzzle).

If you wanted to make it really tricky, you could have a part of the puzzle that can only be solved with light. That way, you need to both have light and have the means of blocking it off, so that it only functions when you have the means of doing both (like a Shadow Sorcerer being able to cast Darkness during the day).

[JackPhoenix]

While understandable for gameplay purposes, it sounds kinda weird from in-character perspective to have a puzzle as a security measure. Blood sacrifice and a password is a good combination, and the trap when you fail to do it correctly makes sense, but what's the point of revealing the password to anyone who goes through the hoops to interact with the puzzle? The creator(s) already knows the password, and nobody else is supposed to.

[Man_Over_Game]

While understandable for gameplay purposes, it sounds kinda weird from in-character perspective to have a puzzle as a security measure. Blood sacrifice and a password is a good combination, and the trap when you fail to do it correctly makes sense, but what's the point of revealing the password to anyone who goes through the hoops to interact with the puzzle? The creator(s) already knows the password, and nobody else is supposed to.

Don't make it a static password. You could, for example, make it a clock that requires something specific to that moment to release the lock.

This does prevent things like Detect Thoughts or torture from revealing the answer, but trying to justify any reason for the elaborate puzzles players go through ends up just spoiling the fun.