Invisible with a light source

[Cheesegear]

A creature is wearing or carrying an object that sheds light.
Said creature goes Invisible. Objects that they are wearing or carrying are also Invisible.

Is the object still shedding light?

[Unoriginal]

A creature is wearing or carrying an object that sheds light.
Said creature goes Invisible. Objects that they are wearing or carrying are also Invisible.

Is the object still shedding light?

I'd say it would be shedding invisible light.

So a creature with True Seeing would see the invisible creature, the object they carry, and the light the object is shedding, for example.

[EggKookoo]

If the invisible creature with the invisible light source is in an otherwise dark room, and doesn't possess truesight, is it effectively blind?

[Unoriginal]

If the invisible creature with the invisible light source is in an otherwise dark room, and doesn't possess truesight, is it effectively blind?

Unless they have Darkvision, yes.

[Asmotherion]

Not sure if this was 5e or 3.5e but I remember a rule that says the invisible item still sheds light, you just can't see the source.

[RSP]

If the invisible creature with the invisible light source is in an otherwise dark room, and doesn't possess truesight, is it effectively blind?

Depends on how the DM rules on if “light” is something the target is “carrying”.

[Mastikator]

Not sure if this was 5e or 3.5e but I remember a rule that says the invisible item still sheds light, you just can't see the source.

So you would just see an outline of pure light?

[RSP]

So you would just see an outline of pure light?

I imagine you would see 20’ of bright light (or whatever the radius is), but no outline: the light would fill in the invisible space, same as it would if it wasn’t being held by the target of Invisibility, but was still filling the area.

[Asmotherion]

So you would just see an outline of pure light?
I think you can see the light, and can figure out it's source based on shadows, but you can't see the source.

[CapnWildefyr]

I think you can see the light, and can figure out it's source based on shadows, but you can't see the source.

Agreed. You'd see a circle of light in the middle of a larger circle of dim light. That might "give your position away" in the general sense but you still get the advantages of invisibility (unless you're targeted by fireball or some other AOE where close enough counts).

This may not be RAW, but to me light from a torch or whatever it not an instant thing. That would be a flashbulb. Instead, it is "generated" continuously and released, and once released, is not subject to the spell any longer (just like if I drop something I was carrying, it appears "out of thin air').

[Yora]

I had not thought about it before, but I think you should even see the flame of an invisible torch.

I also just realized that the description of the invisibility spell means that you can see the breath of invisible creatures in cold conditions. Not sure what I would do with that mechanically if it comes up, but could be an interesting detail in some situations.

[Mastikator]

This is the problem with trying to combine modern physics and magic based on Aristotelian physics. Fire doesn't cast a shadow, the light you see is its black body radiation. If invisibility allows light to pass through you then you don't cast a shadow and can't be seen, but glowing things like fire IS visible. If invisibility also prevents fire from being visible it should prevent it from casting light. A glowing object either is visible or doesn't glow, if you can see the light emitted then you are looking at the object. You can see it.

[Aelyn]

I don't think RAW gives a clear answer to this.

As a DM, I would say that the light itself is visible and apparent, but it's not immediately clear where exactly it's emanating from. I'd allow non-mindless NPCs to make either a Perception or Investigation check to figure out where exactly the light's coming from in order to target the bearer, which I'd treat as a bonus action. Note the attacker would still have Disadvantage on any attack rolls against the invisible target.


I'd say it would be shedding invisible light.

So a creature with True Seeing would see the invisible creature, the object they carry, and the light the object is shedding, for example.

I'm aware of at least one Harry Potter fanfic where this exact approach is used as a trap against people who can see invisibility - a charm that produces an invisible but dazzlingly bright illusion, meaning most people are unaffected but the truesight character is temporarily blinded. I'd almost be tempted to use this approach purely to allow a clever PC to use the same tactic!

[EggKookoo]

This is the problem with trying to combine modern physics and magic based on Aristotelian physics. Fire doesn't cast a shadow, the light you see is its black body radiation. If invisibility allows light to pass through you then you don't cast a shadow and can't be seen, but glowing things like fire IS visible. If invisibility also prevents fire from being visible it should prevent it from casting light. A glowing object either is visible or doesn't glow, if you can see the light emitted then you are looking at the object. You can see it.

Right. Light illuminating an area like a wall is, from a physics perspective, no different from light tickling your retinas. If it can light up the wall, it'll "light up" your retinas. That's what seeing is.

This is why I interpret illusory magic, including invisibility, as a partially mental effect. There's some basic light manipulation going on, but there's also a kind of charm effect on the viewing creature that convinces it of the reality of the illusion.

[Cheesegear]

This is the problem with trying to combine modern physics and magic based on Aristotelian physics...

Part of me wants to respond with 'Well it depends; Is light a particle or a wave?'

I ended up ruling that magical light that effects the object (e.g; Light) becomes a property of the object, thus, turning it Invisible. The same way that invisible armour wouldn't reflect moonlight or something. The property of shedding light, is part of the object, and thus, Invisible. Go to Darkvision.
(Whether or not you can see the light using Truesight is a really stupid bridge that I don't want to cross, and thankfully probably wont ever come up ever.)

When it comes to non-magical light (e.g; a torch), the part that gives off the light (i.e; fire), is not part of the object, and thus does not turn invisible. Creatures would simply see floating fire, which would be incredibly odd.

[Mastikator]

Right. Light illuminating an area like a wall is, from a physics perspective, no different from light tickling your retinas. If it can light up the wall, it'll "light up" your retinas. That's what seeing is.

This is why I interpret illusory magic, including invisibility, as a partially mental effect. There's some basic light manipulation going on, but there's also a kind of charm effect on the viewing creature that convinces it of the reality of the illusion.

A torch will illuminate an area by emitting light in all directions, that light hits the stuff around it, then bounces into your eyeballs. That's how you see stuff illuminated by the torch. Fine. You can also see the torch by the light emitted by the torch, the light from the flame is NOT a reflection, it's the emission. Your eyes don't care whether light is reflected or emitted. But the invisibility spell does care. Because invisibility prevents reflection, so you can't see invisible objects because they don't reflect light. BUT emission is a different matter.

Either
a) invisible objects can not emit light, the fire from the torch does not emit light and does not illuminate the area and you can't see it or
b) invisible objects can emit light, the fire from the torch does emit light, you can see the illuminated area as well as the fire from the torch or
c) you need to redefine what light. And you will definitely run into huge game breaking problems so pick a or b

[Carpe Gonzo]

If you hold an invisible mirror and a light is shined on it, can it redirect the light or does it pass through or both? Technically, all the Invisible condition says is that an anything that is invisible is "impossible to see" and "for the purposes of hiding, is Heavily Obscured"

[KorvinStarmast]

Not sure if this was 5e or 3.5e but I remember a rule that says the invisible item still sheds light, you just can't see the source. check out the light cantrip:

If you target an object held or worn by a hostile creature, that creature must succeed on a Dexterity saving throw to avoid the spell. On some enemies this isn't much help (giant constrictor snake, for example) but for most humanoids it can make their attempts to hide or go invisible a problem.

[EggKookoo]

A torch will illuminate an area by emitting light in all directions, that light hits the stuff around it, then bounces into your eyeballs. That's how you see stuff illuminated by the torch. Fine. You can also see the torch by the light emitted by the torch, the light from the flame is NOT a reflection, it's the emission. Your eyes don't care whether light is reflected or emitted. But the invisibility spell does care. Because invisibility prevents reflection, so you can't see invisible objects because they don't reflect light. BUT emission is a different matter.

Either
a) invisible objects can not emit light, the fire from the torch does not emit light and does not illuminate the area and you can't see it or
b) invisible objects can emit light, the fire from the torch does emit light, you can see the illuminated area as well as the fire from the torch or
c) you need to redefine what light. And you will definitely run into huge game breaking problems so pick a or b

In order for any of this to work I have to separate mechanical effects from narrative effects. I know this bugs a lot of people but illusions and related stuff are all weird and require weird solutions. So, an illusory torch emits light in the narrative sense but not in the mechanical sense. Meaning a creature sees emitted light from the torch but functions mechanically as though no light is emitted. If the illusory torch is the only "light source" in the area, the creature thinks the area is lit up but still suffers the mechanical effects of darkness (disadvantage on attacks, etc.).

As I mentioned before, I justify the cognitive discrepancy this often creates by assuming illusion magic, in addition to creating some amount of optical effect, is also convincing an observing creature that what its seeing is real. It's not real, and may even be completely false visual information, but the creature doesn't get that. At least until it overcomes the mental effect (typically through a successful Investigation check) and then is only affected by the (feeble) optics. It's at that point that the creature stops thinking the illusory torch is lighting up the room and only sees the weird flat thing that is glowing but also not really casting off any light.

It's nonsense, to be sure, but that's what illusions are. There's a reason why Star Wars style holograms are as much fantasy as hyperspace.

[Lord Vukodlak]

Yes the light is visible, if it wasn’t then the spell faerie fire wouldn’t work.

[Demonslayer666]

Keep it simple. It's magic. You and what you carry are invisible, everything else works normally.

Let the light source work like a light source, but you and the light source are invisible, including flames. Whether it affects the observers mind or how light works, it doesn't matter and doesn't need to be figured out.

Edit: And invisible creatures don't cast shadows.

[EggKookoo]

Keep it simple. It's magic. You and what you carry are invisible, everything else works normally.

Let the light source work like a light source, but you and the light source are invisible, including flames. Whether it affects the observers mind or how light works, it doesn't matter and doesn't need to be figured out.

Edit: And invisible creatures don't cast shadows.

Doesn't work for my players. They want to do things like light a real candle, put an illusion of a box around the candle, and ask if the room is still lit up. If so, then ask if they can see the candle through the box (because the walls "can"). Or ask if they can see their faces in illusory cutlery, and if they can't (because illusions can't cast reflections) ask why the spoon isn't pure black.

[RSP]

Doesn't work for my players. They want to do things like light a real candle, put an illusion of a box around the candle, and ask if the room is still lit up. If so, then ask if they can see the candle through the box (because the walls "can"). Or ask if they can see their faces in illusory cutlery, and if they can't (because illusions can't cast reflections) ask why the spoon isn't pure black.

Because Magic.

I’d have a chat with the table about how D&D isn’t a real world simulator, and you’re going to rule on interactions without having to design/explain a world where physics+magic makes sense.

Kudos to you if you have the capacity to do that and have everything make sense (I certainly don’t), but working all that out is going to bring sessions to a standstill while you do, whenever a question comes up.

“Hey, we’re going with this interaction because magic” is a much easier way to deal with such things on the fly, without stopping play.

[Silly Name]

Doesn't work for my players. They want to do things like light a real candle, put an illusion of a box around the candle, and ask if the room is still lit up. If so, then ask if they can see the candle through the box (because the walls "can"). Or ask if they can see their faces in illusory cutlery, and if they can't (because illusions can't cast reflections) ask why the spoon isn't pure black.

I have to second the sentiment that trying to apply modern real-world physics to magic doesn't really work. Magic, by its very definition, eschews the limits and laws of physics as we understand it.

Does the illusory box stop light? It's up to you - intuitively, I'd say yes, since it stops vision in a general sense, but maybe you want this to be a peculiarity of spells of a certain level and higher, or maybe not.

Why is that an illusory spoon doesn't reflect images but doesn't appear as a pure black? Because it's a magical illusion that operates under different rules from every day mundane objects.

[EggKookoo]

Because Magic.

They already know that. "Because magic" is the starting point. They want to know "why because magic?" or "because magic how?" That's what they're trying to understand.

I try to give my players challenges that require them to use their imagination and inventiveness. Sure, D&D is a lot about kill da orc, but it's also a lot about getting into the heads of your PCs and trying to figure out who was that shadowy figure that stabbed the noble and vanished in a puff of smoke. Or here's a bunch of sculptures and a magical, impassable door. Maybe I dunno how should you arrange the sculptures to create an effect that opens the door? I want them to work out the underlying principles of things so they can use that knowledge to get deeper into the game. I want them to trust that the world makes some internal sense.


I’d have a chat with the table about how D&D isn’t a real world simulator, and you’re going to rule on interactions without having to design/explain a world where physics+magic makes sense.

It's not about simulating anything so much as it's trying to work out how things work within the fantasy. Less realism and more consistency. If they know illusions manifest a certain way, they can understand how someone might later be fooled by one, or how their characters managed to see past one. It gives them a reason to believe in the fiction. "Because magic" is telling them they shouldn't believe in the fantasy because it's just a game. It's "stop asking questions about the fantasy." It's a way of shutting down their imaginations.


Kudos to you if you have the capacity to do that and have everything make sense (I certainly don’t), but working all that out is going to bring sessions to a standstill while you do, whenever a question comes up.

What's telling to me here is you say discussing stuff like this brings the session to a standstill, but to me (and my players), it is the session. Getting into how it all works is probably 50% of why we're there.


“Hey, we’re going with this interaction because magic” is a much easier way to deal with such things on the fly, without stopping play.

As a temporary measure, sure. We'll get into the specifics once this encounter is over. Or even after the session. But we'll get into it at some point, because it strengthens the fantasy.


Why is that an illusory spoon doesn't reflect images but doesn't appear as a pure black? Because it's a magical illusion that operates under different rules from every day mundane objects.

So here's the problem. What does the spoon look like? When I look at it and don't see my face, what do I see?

This is a literal question asked to me by a player. I realized pretty quickly that if chrome/shiny illusions didn't reflect their surroundings, they would immediately look fake, at least at any kind of short distance. They would fool no one (this problem expanded right away to flickering illusory candlelight and other similar effects). I ruled then and there that the spoon reflected the PC's face back at him, and justified it by saying the spoon wasn't really reflecting anything in a physics sense, it just had the illusion of a reflection, and admitted that there's really no practical difference. That left open the question of if a spoon can create the illusion of a reflection, why can't a wall mirror? But luckily there were no illusory wall mirrors involved so I didn't have to deal with it right then and there.

[RSP]

They already know that…But we'll get into it at some point, because it strengthens the fantasy.

Then yes, you need to try to anticipate every possible illusion your players will encounter, and figure out how they’ll differ. Then come up with an in-game science that explains it all.

If that’s what floats the boat at your table, invite the Players in on the discussion to cover everything they can think of as well.

If you end up with a unifying theory for the in-game science of 5e illusions, please share (though this might be affected by which setting you use, not sure how those will differ).


I realized pretty quickly that if chrome/shiny illusions didn't reflect their surroundings, they would immediately look fake, at least at any kind of short distance.

This, in my view, is why an Investigation check reveals illusions for what they are: if they didn’t have errors, there’s be no way to know them as illusions.

[EggKookoo]

If you end up with a unifying theory for the in-game science of 5e illusions, please share (though this might be affected by which setting you use, not sure how those will differ).

I have one but people tend not to like it. I mentioned it above. Illusions are a combination of optical and mental trickery. The optical stuff is flimsy and not terribly convincing on its own. The mental part is akin to a charm, convincing you that the optical part is real. Determining the true nature of an illusion breaks the mental trickery, leaving behind the optical. This is why illusions become flat, semitransparent, or otherwise indistinct once you make that Investigation check.


This, in my view, is why an Investigation check reveals illusions for what they are: if they didn’t have errors, there’s be no way to know them as illusions.

I agree, but in order for it to be worthy of a check, it needs to be convincing at a glance (or, rather, being able to withstand a casual inspection). The reflection you see in the spoon is in your mind. Just like the real light from the real candle being blocked by the illusory box. The room is still being lit, but the magic has convinced you that you don't see it. Your eyes see the flame of the candle inside the box, but your mind refuses to accept it. What's weird is your pupils probably contract when looking at the candle.

Now, as to the principles behind how the mental trickery works... :smallbiggrin:

[Imbalance]

Play any amount of Skyrim if you have trouble imagining lighting effects with no visible source (as well as the occasional lit torch that casts no light - see Forelhost Crypt for instances of both).

[HPisBS]

It's not about simulating anything so much as it's trying to work out how things work within the fantasy. Less realism and more consistency. If they know illusions manifest a certain way, they can understand how someone might later be fooled by one, or how their characters managed to see past one. It gives them a reason to believe in the fiction. "Because magic" is telling them they shouldn't believe in the fantasy because it's just a game. It's "stop asking questions about the fantasy." It's a way of shutting down their imaginations.

This. So much this.

[RSP]

I agree, but in order for it to be worthy of a check, it needs to be convincing at a glance (or, rather, being able to withstand a casual inspection).

Keep in mind, the Investigation check is a casual inspection (it can happen in less than 6 seconds - during a turn of combat).

I use silverware everyday for meals: very rarely do I check if it’s able to give me a semblance of my reflection (though I’ve never been worried about the spoon not being real - at least not since the original Matrix was popular).

I also go with illusions are just illusions and don’t do things like reflections (barring using Major Image and using an Action to adjust the illusion to show said reflection, if relevant). The “charm” thing wouldn’t work for me as, at the least, that would then need to be a Wis Sv rather than an Investigation check to notice imperfections.

Outside of Invoke Duplicity, illusions will have their faults that can be noticed. Whether a character noticed such things or not, if I’m DMing, is probably determined either by RP or an Investigation check (possibly a passive Investigation check).

[Chronos]

Personally, I rule that illusionary mirrors (except for maybe the high-level quasi-real ones) can't produce faithful reflections, because allowing that opens up way too much abuse for someone who knows a bit of optics. An illusion might, however, include something that would pass for a reflection on casual inspection, like a glint of sunlight off the edge of an illusory sword's blade.

We already know that illusions aren't perfect, because a lucky Investigation check can reveal them. So I feel comfortable saying that this is just one of the imperfections.

[EggKookoo]

I also go with illusions are just illusions and don’t do things like reflections (barring using Major Image and using an Action to adjust the illusion to show said reflection, if relevant). The “charm” thing wouldn’t work for me as, at the least, that would then need to be a Wis Sv rather than an Investigation check to notice imperfections.

I wouldn't say it's literally a charm effect. I don't think elves have any particular resistance to illusions. I just mean it's a mental effect. But I also think you should be able to use Wisdom (Investigation) to detect illusions and I'm happy to allow that.


Personally, I rule that illusionary mirrors (except for maybe the high-level quasi-real ones) can't produce faithful reflections, because allowing that opens up way too much abuse for someone who knows a bit of optics. An illusion might, however, include something that would pass for a reflection on casual inspection, like a glint of sunlight off the edge of an illusory sword's blade.

I rule that an illusory mirror appears to cast a reflection if the creator of the illusion wants it to. What it appears to reflect depends on the viewer. Most likely you see what you'd expect to see in a real mirror in that particular location. If someone was standing behind you and you weren't aware of it, you wouldn't see that person in the reflection.

[Segev]

Count me in with the group that says that you can see things illuminated by the light source, but the light source itself is invisible. So you have this circle of lit ground, objects lit as if by the light source within that space, but you can't see the source of the light.

[RSP]

I wouldn't say it's literally a charm effect. I don't think elves have any particular resistance to illusions. I just mean it's a mental effect. But I also think you should be able to use Wisdom (Investigation) to detect illusions and I'm happy to allow that.


Sure, it’s your interpretation: I just think if it’s affecting the mind of others, that should warrant a Wis Sv, and I’d not want that in my games as a staple of illusions.

[Rukelnikov]

Count me in with the group that says that you can see things illuminated by the light source, but the light source itself is invisible. So you have this circle of lit ground, objects lit as if by the light source within that space, but you can't see the source of the light.

This is also how I've always ran it.

However... there is a trickier situation, what happens if i'm carrying a shut bullseye lanters, which wouldn't be sheding light, and then I cast invisibility on myself? Am I now sheding light all around :smallbiggrin:?

[Glorthindel]

Personally, I rule that illusionary mirrors (except for maybe the high-level quasi-real ones) can't produce faithful reflections, because allowing that opens up way too much abuse for someone who knows a bit of optics. An illusion might, however, include something that would pass for a reflection on casual inspection, like a glint of sunlight off the edge of an illusory sword's blade.

That's the way I would go. For example, in the case of the spoon, the character would see a smudgy, coloured reflection that could be the reflection of their face in an unpolished, slightly dirty reflective surface, but is really just the illusions attempt to replicate a reflective surface. Detailed inspection would reveal the lie, but that requires the Investigation Test that the illusion requires.

[dehro]

I would rule that the light is still visible.. the character that goes invisible isn't carrying the light, only the light source, which indeed goes invisible.
same for a glass of water... if the invisible character holds a glass of water, all goes invisible..if the character tosses the water out of the glass, he effectively stops carrying it, so the water becomes visible the moment it leaves the glass. I would consider the same for any light held by an invisible character.

[Grim Portent]

Wouldn't the simplest interpretation of Invisibility be that anything effected by it is rendered 100% transparent? No faffing about with the emission or reflection of light, or massaging how living things nearby see, any and all light just passes through all parts of the subject as if there was nothing there other than normal air. If the subject emits light, it still emits it when invisible, and it passes through the subject like all other light does.

[Segev]

This is also how I've always ran it.

However... there is a trickier situation, what happens if i'm carrying a shut bullseye lanters, which wouldn't be sheding light, and then I cast invisibility on myself? Am I now sheding light all around :smallbiggrin:?

DM's call, but I would rule the lantern as the light source because it is treated that way in the rules. You could certainly make the physics-based case for it turning into a candle or regular lantern for how much light it sheds and in what directions (all). Seems like less confusion if it just works as normal, but with the lantern invisible, to me, though.

[EggKookoo]

Sure, it’s your interpretation: I just think if it’s affecting the mind of others, that should warrant a Wis Sv, and I’d not want that in my games as a staple of illusions.

At the same time, it's a pretty good argument that you defeat an illusion as an act of exceptional perception, which would invoke Wisdom. Honestly I'm not sure why the RAW uses Investigation over Perception with regard to illusions, except maybe to say that illusions are always perfect with regard to your senses, but "logically" inconsistent in some way. But even still, there would be a lot of overlap between the two, just as there is with Acrobatics and Athletics.


However... there is a trickier situation, what happens if i'm carrying a shut bullseye lanters, which wouldn't be sheding light, and then I cast invisibility on myself? Am I now sheding light all around :smallbiggrin:?

I would rule that the light source is rendered invisible along with the lantern it's in. Which means it's technically shedding light, but that light is also invisible. It wouldn't illuminate your surroundings to anyone unable to see past your invisibility.