Night Vision vs. Ultraviolet Vision

[LoneWolf]

1 hour ago, Gauntlet said:

I, a lot of times, will not allow Nightvision as it really gives you too much. I mean what is the point of getting IR or UV vision if Nightvision is available. Maybe in a Champions game it would be okay but definitely not in a heroic game. I give underground dwellers IR vision to see underground and night creatures who do not go underground, such as elves, UV vision to see at night.

 

It really depends on the campaign.  In a science fiction-based game there are probably a lot of infrared and ultraviolet devices.  Having those visions will allow you to see them.  For example, Infraredvision would allow you to see an infrared signal.  In the real world a lot of devices like TV’s and stereo systems have infrared remote controllers.  In a high tech setting those are going to be even more common. Infraredvision also allows you to detect heat so can give more information than sight.  A character with infraredvision could be able to determine if an electronic device was on by the fact, it has a higher temperature from the heat of the electronics.  In a Fantasy campaign it can help you spot an undead creature due to its lack of body heat. 

 

Ultraviolet Light also give more information than visible light.  Many substances show up differently under ultraviolet light.  Ultravioletvision could allow a character to detect those substances easier. For Example, it would be able to detect urine and other body fluids after they have dried.  That is how the pet urine detectors work.   It can help in determining fakes and counterfeit money.  

 

All night vision does is to allow you to see in the dark.  
 

[MrAgdesh]

8 hours ago, Lord Liaden said:

 

Absolutely. How it works in HERO is a legacy of early D&D. But at this point the concept has become so ingrained in the wider gaming subculture, it's an accepted convention in many games.

This is basically what they have said. Modern D&D has “Dispelled Ultravision as a nonsense” 

 

Elsewhere online “it would be like illuminating a niteclub with a black light” 

[MrAgdesh]

10 hours ago, Gauntlet said:

I, a lot of times, will not allow Nightvision as it really gives you too much. I mean what is the point of getting IR or UV vision if Nightvision is available. Maybe in a Champions game it would be okay but definitely not in a heroic game. I give underground dwellers IR vision to see underground and night creatures who do not go underground, such as elves, UV vision to see at night.

 

'Darkvision' in 5E D&D seems to be an amalgam of Real World Low Light (such as possessed by your typical house cat) and near-IR. so in HERO terms its both Nightvision and IR Vision combined.

 

Whilst its been proven that many mammals can see in the UV spectrum, a cat (for example) does not utilise this in particular to see better in dim light than we do. It is the structure of a cat's eye in that the vertical slit pupils are able to control more light coming in (than ours) and the presence of a tapetum lucidem to reflect that visible ambient light back through the retina.

 

UV vision at night does not give "clear as daylight vision" as per HERO. It would allow for certain observations such as seeing phosphorescent urine traces and bodily fluids and even such things as flowers differently (such as those that pollinate by creatures such as moths). In fact, I am reminded of Arthur Morgan's Red Dead Redemption II Eagle Eye ability.

 

It may also be an evolutionary adaptation in seeing within the UV spectrum as most creatures that can do so do not typically have a long lifespan (more than two decades or so). This would be to counter the blindness that would occur from such exposure (humans have a cornea and lens to protect the retina).

 

Hmm... Gaming wise, vampires quite probably have UV (which would explain their aversion to sunlight) and probably grow a tapetum lucidum as part of their Turning (which would explain the cat's eyeshine). Their regeneration probably counters any long term retina damage.

 

Elves on the other hand, with UV, would need to restrict themselves to heavily wooded forests (makes sense) but certainly wouldn't come out in the summer without sunglasses. 

 

As an aside: I note that 'Nightvision' as an Enhanced Sense first appears in 5E Hero.

[Christopher R Taylor]

IR gives you details and information that night vision would not.  I define nightvision in my campaign as "enhances available light" so it doesn't help underground, for instance, without a light source.  IR works everywhere, and further, makes hot things (like enemies) stand out against the background.

[unclevlad]

IR doesn't help to identify something that matches the background temperature.  It's also very coarse;  it's a heat map.  You can get rough shape because the core radiates more heat than the head or limbs...but it doesn't have IFF, and probably shouldn't support precise targeting, like aiming for something specific.  In many cases, you'd need to infer that, say, the person you're seeing with IR alone has a rifle;  the rifle's likely at ambient temp.

 

But hey, we're simplifying things for game play.  None of the senses work IRL as well as the game allows them to work.

 

From a game perspective, I think the point of this thread is that night vision and UV have almost complete overlap.  UV is, however, inferior by definition.  So why do they cost the same?

 

The point about Night Vision is new in 5E...hmm...<opens up 4E PDF>

 

IR..."the character has normal PER rolls at night, but can only perceive outlines of people and objects."
UV...can see at night as long as there's some UV around.  

 

That IR text is really bad.  It's basically contradictory, or at best poorly structured.  Low light amplification...night vision...has little to do with IR detection.  I suspect Nightvision was incorporated to avoid this.  UV didn't change.  The fact that both exist is probably systemic inertia.

 

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16 hours ago, LoneWolf said:

Ultraviolet Light also give more information than visible light.  Many substances show up differently under ultraviolet light.  Ultravioletvision could allow a character to detect those substances easier. For Example, it would be able to detect urine and other body fluids after they have dried.  That is how the pet urine detectors work.   It can help in determining fakes and counterfeit money.

 

 

Yes, but this is based on using a relatively high-intensity source.  Does UV perception, based only on ambient UV, have enough resolution on its own?  If that's true outside, is it true indoors?  Nor does someone need UV perception for those applications;  the utility comes from the fluorescence caused by the UV source.

 

UV perception can provide some additional benefits...but by and large, yeah, it's an inferior choice.  It should be less expensive than Nightvision or IR.

 

 

 

 

 

[Gauntlet]

16 hours ago, LoneWolf said:

 

It really depends on the campaign.  In a science fiction-based game there are probably a lot of infrared and ultraviolet devices.  Having those visions will allow you to see them.  For example, Infraredvision would allow you to see an infrared signal.  In the real world a lot of devices like TV’s and stereo systems have infrared remote controllers.  In a high tech setting those are going to be even more common. Infraredvision also allows you to detect heat so can give more information than sight.  A character with infraredvision could be able to determine if an electronic device was on by the fact, it has a higher temperature from the heat of the electronics.  In a Fantasy campaign it can help you spot an undead creature due to its lack of body heat. 

 

Ultraviolet Light also give more information than visible light.  Many substances show up differently under ultraviolet light.  Ultravioletvision could allow a character to detect those substances easier. For Example, it would be able to detect urine and other body fluids after they have dried.  That is how the pet urine detectors work.   It can help in determining fakes and counterfeit money.  

 

All night vision does is to allow you to see in the dark.  
 

 

You definitely make some good points.

[LoneWolf]

I am not an expert on how UV light works, so the information I am using is from the internet and using the cheap pet urine detectors.

 

The pet urine detector I have uses a couple of AAA batteries and does not seem very bright.   That leads me to believe it is not that high intensity.   It is also designed to allow someone without any other equipment or the ability to see in the UV spectrum to see body fluids.  Someone with the natural ability to see in the UV spectrum probably can use it to detect what the flashlight does.  I am not sure how it would show up but I imagine the color would be different because the UV light is being reflected back to the retina of the character.  

 

Since UV light is not detectable by normal sight having a source of UV light would allow you to see, but characters without UV vision would not be able to see the light. 

 

Maybe the solution would be to change UV Vision to an active sense for the same cost.  That would allow it to be used anywhere but would be visible to other with UV vision. That would give each of the three senses some differences and advantages.  IR vision would give the ability to see things that are a different temperature and work anywhere but would not be detectable. Night Vision would allow you to see as you normally do in complete darkness and would also not draw attention to you.  UV Vision would work everywhere and allow you to some advantages in detecting certain things but would draw attention to you. 

[Gauntlet]

One of the big advantages over UV vision over IR is that it can give more detail. With UV you can read a written document, while with IR you would not be able to. IR's big advantage is that it can be used almost anywhere as most things will have a different heat amount. So even if you are completely underground with no light at all you can still see what is around you. IR would still even see undead as their bodies will still have a slightly different heat value then the air around them. Different materials have a tendency to have different heat values. though for both of these you probably will want to give the person with the vision to have it discriminatory as well. 

[unclevlad]

38 minutes ago, LoneWolf said:

I am not an expert on how UV light works, so the information I am using is from the internet and using the cheap pet urine detectors.

 

The pet urine detector I have uses a couple of AAA batteries and does not seem very bright.   That leads me to believe it is not that high intensity.   It is also designed to allow someone without any other equipment or the ability to see in the UV spectrum to see body fluids.  Someone with the natural ability to see in the UV spectrum probably can use it to detect what the flashlight does.  I am not sure how it would show up but I imagine the color would be different because the UV light is being reflected back to the retina of the character.  

 

Since UV light is not detectable by normal sight having a source of UV light would allow you to see, but characters without UV vision would not be able to see the light. 

 

Maybe the solution would be to change UV Vision to an active sense for the same cost.  That would allow it to be used anywhere but would be visible to other with UV vision. That would give each of the three senses some differences and advantages.  IR vision would give the ability to see things that are a different temperature and work anywhere but would not be detectable. Night Vision would allow you to see as you normally do in complete darkness and would also not draw attention to you.  UV Vision would work everywhere and allow you to some advantages in detecting certain things but would draw attention to you. 

 

UV isn't visible, so, no, it won't appear bright.  However, it's FAR brighter than the background UV...or you wouldn't need need the UV source, you'd be able to spot the fluorescence emitted by the pet urine.

 

You see the fluids because compounds in those fluids absorb the UV frequencies...and what goes in, must come out...but not at the same frequency.  They're re-emitted in the visual spectrum.  The brightness of this is gonna be tied to the intensity of the UV.  UV-A, the less problematic kind, has an intensity of 6 mW/cm^2, or about 60 watts per square meter.  Sunlight overall?  1300 watts per square meter.  And that's outdoors...not indoors.  The only UV would be reflected, like from the house next to me.  A pet urine detector is using a frequency in the UV-A range...but it's also suggested to do this in a dark, or at least dark-ish, room...because the light emitted back will get drowned out by the sunlight.  

 

Logitech still makes their solar powered keyboard.  Couple solar panels on it.  You can get an app that shows the light intensity on those panels.  Take a small-ish bulb...start at 2' away, you'll get one reading.  Move it to a foot away...and it'll be 4x higher.  Because light intensity follows an inverse-square pattern...given a source of brightness B, the intensity at distance d is B /  (d^2)...so even if B is typically really low...a few LEDs' worth...if it's very close to the solar panel, it offers a great deal more charge than, say, overhead room lights.

 

But the urine itself is NOT emitting UV.  It's reacting to the UV that strikes it.

 

Yes, the side benefit for UV is things like UV flashlights, or UV signs/markers...most people wouldn't see them.  That's a pretty darn fringe use, tho.

 

UV is no more active than normal sight or IR.  It's purely a matter of which chunk of the spectrum you can register.  Rather than try to force-feed UV into something, I'd go the other way...and either make it super cheap, as it has little utility, or build it into night vision as a side perk...and drop it as a standalone.

 

 

 

   

[MrAgdesh]

I'd say UV Perception needs to be cheaper. Maybe 3pts, same as Ultrasonic. It's useful for very specific functions such as forensics and clue hunting. Niche, CSI type stuff. Still has its place but it doesn't work as the book says. For seeing in the dark you have IR or Nightvision (but basic IR isn't Discriminatory so exactly what you can pick up with this is GM discretion).  

[unclevlad]

You *don't* use UV Perception for forensics.  You're still backwards here.  You use the UV source to cause a visible effect.  To use UV perception, what you're looking for would have to be emitting in UV, intensely enough to be noticed.  Black body radiation describes the curve of radiation across the spectrum, for a body of a given temperature.  The UV emitted is negligible...until you start talking temperatures of around 2000 K...1700 C.  Steel's melting point range is about 1375 to 1530 C, depending on the alloy.  That's also about 3000 F...lava's 2000-2500.  

 

There are room temp ways to create UV...obviously, as tanning beds do it, or the urine detection flashlights, but these involve electrical energy raising the energy of electrons in the emissive material;  that's a temporary change.  When the excited electrons return to their ground state...they emit a photon.  The right material, that photon's in the UV range.

EDIT...to finish that...IR perception goes the *other* way.  IR is also photons, but they're lower energy, longer wavelengths, than visual light.  Most black body radiation is in the IR spectrum.  It's the same mechanism why something really hot goes from dark, dull red...very little visible spectrum emission, to red (more) to orange (hotter) to yellow, etc.

[LoneWolf]

Humans cannot see in the UV spectrum so all our UV technology is making it visible to the normal spectrum.  If someone has the ability to perceive in the UV spectrum this does not need to be done.  How they view things are going to be different. I see no reason they could not use ambient UV light to get information about an object.  Instead of glowing in a dark room it would probably show up as a slightly different color that someone with normal human vision could not see.  In effect normal humans are color blind to UV colors. 

 

According to Wikipedia reflective UV photography is used in medicine, dermatology, botany, criminology and theatrical applications. Reflective UV photography can use strong natural sunlight. A filter is used to block visible and infrared light so only the UV light passes through the lens.  That is technology we currently have.  Imagine what can be done in the future or by a super scientist like reed Richards.   
 

[unclevlad]

14 minutes ago, LoneWolf said:

Humans cannot see in the UV spectrum so all our UV technology is making it visible to the normal spectrum.    
 

 

Yeah, but....  What's going on is that emitted (or reflected) UV is measured, likely at a variety of wavelengths, and this is mapped to a defined color and luminosity palette...that's the process that radio telescopes use to produce, for example, the images of nebulae.

 

 

 

 

 

 

 

Same nebula...I forget which.  Forget what the difference is, I think the top one is from Webb, which has higher resolution.

 

21 minutes ago, LoneWolf said:

According to Wikipedia reflective UV photography is used in medicine, dermatology, botany, criminology and theatrical applications. Reflective UV photography can use strong natural sunlight. A filter is used to block visible and infrared light so only the UV light passes through the lens.  That is technology we currently have.  Imagine what can be done in the future or by a super scientist like reed Richards.   
 

 

Reflective UV is using the sun as the UV source...ok.  In sunlight, then, there might be *some* additional information to be gained...if the perceiver has the skill to know what the information is even telling him.  That still needs an external source...strong natural sunlight is the source there, but what about at night, or indoors?  OK, I'll grant that analyzing UV reflections might tell you something...in areas where you're knowledgeable enough, and when you bring a UV source.

 

But that's still serious fringe value, and still dependent, in most situations, on having a piece of gear to be the UV source.  

 

I'll actually suggest a further step.  Drop UV perception altogether.  Just use Detect Radiation, in the Sight group.  Natural understanding would be, this covers gamma and x rays...which are photons.  So, fine, UV too.  UV, gamma, and X rays are all higher-energy, and shorter wavelengths, than visible light.  Yeah, it grabs alpha and beta particles too...that's fine with me.  It fits.  This actually gives a simple order, based on frequency:

 

--radio waves are just photons...they're just REALLY long wavelengths...and generally VERY low energy density

--IR

--visible

--supravisible ("radiation")

 

Detect Radiation would now have a solid in-game use...if not exactly a common one, it's one players can understand.  And if you get into the more exotic ones like reflective UV...given a UV source, you can do that too.  

 

 

[Christopher R Taylor]

The challenge is really depicting the difference between nightvision and UV vision.  UV has to have its strengths and weaknesses, but in literature and games it ends up just being violet-hued night vision.  Its said to only work outside where UV light is provided, although the Dark Elves in EverQuest for instance could see clearly underground (it was very superior to IR vision).

 

In game terms I guess you would have to make night vision something that works less well than UV but also works underground, more the "dim outlines" version of 5th edition quoted above, while UV gives clear vision but only with sources of UV light.  Anyway that's how I would do it, I think.

 

Quote

I'll actually suggest a further step.  Drop UV perception altogether.  Just use Detect Radiation, in the Sight group.

 

This is probably the right direction to go in a hypothetical 7th edition.

Edited October 14, 2023 by Christopher R Taylor

[MrAgdesh]

7 hours ago, unclevlad said:

You *don't* use UV Perception for forensics.  You're still backwards here.  You use the UV source to cause a visible effect.  To use UV perception, what you're looking for would have to be emitting in UV, intensely enough to be noticed.  

 

 

OK, for using UV Perception lets use the the example of how a deer spots hunters who have washed their duds in Brighter then White Detergent (TM).

 

I'd still design a blacklight as UV Perception on a Focus for ease of gameplay.

[unclevlad]

9 hours ago, MrAgdesh said:

 

OK, for using UV Perception lets use the the example of how a deer spots hunters who have washed their duds in Brighter then White Detergent (TM).

 

I'd still design a blacklight as UV Perception on a Focus for ease of gameplay.

 

If this is part of a crime scene kit?  I wouldn't even require that.  It's just part of the kit.

[LoneWolf]

 One thing that UV could be useful for is identifying people and objects.  A person or object may look slightly different to UV.  For a person it could be a birthmark that is not visible to normal sight.  A person without UV vision would not be aware of this so would not incorporate that into their disguise.  The character with UV vision that notices the birthmark is missing would have a better chance to see through the disguise. 

 

The other thing it could be used for is to send messages that others do not notice.  Basically you have an ink that is not visible to normal sight but anyone with UV vision can see and read it.  

 

This thread got me thinking on how to use UV vision.  The more I think about it the less important being able to see in the dark becomes. 

[LoneWolf]

Someone earlier was commenting on being in the dark only giving a -4 penalty.   The thing to realize is that your perception roll includes all your senses.  If you make your roll by -4 you detect what you are trying to find by a sense other than sight.  You still cannot see the person in the dark, but you have heard or smelled them.  You still take all the penalties of not having a combat sense, unless of course you have another combat sense.  A -4 is more significant than it seems.  To the person with an 11 perception roll it reduces your chance by 47%, for a 15 or less it is still a 32% reduction.  

[Lord Liaden]

41 minutes ago, LoneWolf said:

Someone earlier was commenting on being in the dark only giving a -4 penalty.   The thing to realize is that your perception roll includes all your senses.  If you make your roll by -4 you detect what you are trying to find by a sense other than sight.  You still cannot see the person in the dark, but you have heard or smelled them.  You still take all the penalties of not having a combat sense, unless of course you have another combat sense.  A -4 is more significant than it seems.  To the person with an 11 perception roll it reduces your chance by 47%, for a 15 or less it is still a 32% reduction.  

 

Nightvision offsets penalties to normal sight. As the default for normal humans, this is the only targeting sense we have. It's irrelevant what other senses you make Perception Rolls with. While I can't speak to how you run your games, in none of the games I've played have I rolled for all my senses every time I check Perception. If there's something I'm looking for or that I might see, I or my GM rolls Sight Perception. If I'm listening for a sound or there's something unusual I might hear, we roll for Hearing Perception. And don't forget that Perception Rolls are for things that characters might miss or are deliberately looking for. If something is considered obvious, there's no roll needed to find it.

 

But as I say, I've been in total darkness. It's not an issue of taking a penalty to see a particular something, it's not possible to see anything. It's like the Darkness Power, completely impenetrable to normal sight, no Perception roll allowed. Now, there can definitely be degrees of darkness in which some light still exists, so that varying penalties can apply. Nightvision is what most nocturnal animals have, so they can see well enough to function normally when illumination is below daylight level. But that's very different from total darkness.

[Gauntlet]

This definitely makes Nightvision much more realistic and usable.

[LoneWolf]

When someone is actively looking for something that is obviously a sight perception roll, but what about when they are not actively looking or listening.  If a character is trying to use stealth on someone who does not know they are there, does the other they get a perception roll to notice them.  Is that a sight only perception roll or does it include all senses.  Also if character is trying to find someone do you allow them separate rolls for each sense?   That would bog down the game considerably.  

[Lord Liaden]

Use what's appropriate to the situation. If someone is trying to sneak quietly behind a person looking the other way, that someone would roll Hearing Perception. If someone is trying to hide in the shadows or within cover like brush, use Sight Perception. If someone is upwind of an animal hunting them, the animal rolls for Smell Perception. Should the GM rule that more than one sense is appropriate to check, one roll could suffice, although multiple rolls would increase the chance of detecting the subject. OTOH if one sense has Perception Modifiers, positive or negative, and the other has a different Modifier, separate rolls would be appropriate.

 

It's not a one-size-fits-all scenario.

[Gauntlet]

3 minutes ago, Lord Liaden said:

It's not a one-size-fits-all scenario.

 

True but I wouldn't let them make all their sense rolls, that would mean give them and incredibly higher chance of noticing. I normally will allow them to make their best roll, but not every roll.

[unclevlad]

3 hours ago, Gauntlet said:

 

True but I wouldn't let them make all their sense rolls, that would mean give them and incredibly higher chance of noticing. I normally will allow them to make their best roll, but not every roll.

 

Then you're kinda hosing them.  They should get all the rolls that apply...and remember, you as the GM decide which senses could be involved.  Hearing...the guy's trying to be stealthy, so make his stealth roll, and that's now a penalty on hearing perception.  Sight may or may not apply.  Smell?  Only if that's a specific giveaway...the Bad Guy has a Distinctive Feature related to smell.

 

No one's saying they get all senses...LL said all senses *that apply.*

 

6 hours ago, LoneWolf said:

When someone is actively looking for something that is obviously a sight perception roll, but what about when they are not actively looking or listening.  If a character is trying to use stealth on someone who does not know they are there, does the other they get a perception roll to notice them.  Is that a sight only perception roll or does it include all senses.  Also if character is trying to find someone do you allow them separate rolls for each sense?   That would bog down the game considerably.  

 

What's the situation?  

 

If someone's using stealth, the typical case would be moving outside the other party's lines of sight.  MOST LIKELY, that's a hearing check;  some others might apply in weird cases.  Alternately...a sense I'm growing more fond of, is based on TK...basically, ranged *touch*.  That'd be another.  Maybe there's a hall mirror the PCs can see...and maybe, maybe not, the sneak flashes in it, or it's a monitor, not a mirror...but the party would have a harder time, in most cases, identifying exactly what the monitor is showing.  If someone is using stealth...make their stealth roll.  However much they make it by, becomes the penalty on perception rolls for that sense.  

 

If you want to give the sneak a chance...perhaps if the stealth roll is good enough (at least by 4)...treat it like Invisibility to the most applicable sense;  for me, that's usually Hearing.  Cross-check the rules on that;  I know Nightvision is built as +4 to sight group, only to offset low light.  But, hearing doesn't have an analogous capability, so giving effective invisibility might be a bit much.

 

There are cases of trying to move sneakily, even in LOS.  Dark night, but not completely dark?  Someone might go with a dark camo look...not all black, but a freeform patchwork of dark grays.  That might be -2 or -3...and the only people who'd get to roll *sight* would be those who're actually looking out...rather than talking by the campfire, or something like that.  

 

7 hours ago, Lord Liaden said:

But as I say, I've been in total darkness. It's not an issue of taking a penalty to see a particular something, it's not possible to see anything. It's like the Darkness Power, completely impenetrable to normal sight, no Perception roll allowed. Now, there can definitely be degrees of darkness in which some light still exists, so that varying penalties can apply. Nightvision is what most nocturnal animals have, so they can see well enough to function normally when illumination is below daylight level. But that's very different from total darkness.

 

This is suggesting the sight group should be narrowed...tremendously.

1.  IR stays...but note that it's NOT dependent on ambient light.

2.  Drop UV, roll it into light amplification...which becomes a sense modifier, not a sense.  Light amplification is basically levels with sight, only to adjust for low intensities.  (IOW, it can help with IR, when what you're trying to perceive is at a very similar temperature to the background.)  

 

Yeah, this makes the Sight Group real small;  IR, and the uncommon Detects based on Sight, like Energy Fields.  But typically, these will also not be affected by ambient light.  You get Ranged and Targeting for free...but you also get that it's subject to being flashed.

[Lord Liaden]

Well, if you don't want to change how the Sight Group functions overall, I would suggest just expanding the darkness penalties. Define "total darkness" as it manifests in most places on Earth, as a -8 to -10 penalty to Sight Perception. For almost everyone that would be impenetrable most of the time, but it would still be possible to counteract the penalty enough to function.

 

Oh, I forgot before: I wanted to address the issues some people have with UV vision used by the D&D Drow to see underground. IIRC in the classic adventure "module," Vault of the Drow, it was specified that the Vault had crystals embedded in the walls which gave off UV light sufficient to illuminate the cavern for its inhabitants. In fantasy worlds with extensive underground environments and habitation -- particularly worlds with magic -- one can establish a similar mechanism throughout the environment which makes UV vision a practical and useful ability.