Curious about infrared and seeing in the dark, who knows stuff?!

[paulewaug]

So the title kind of says it.

What do you guys know about actual night vision and in darkness?

There's Thermal Vision- this would be blobs of color right? Normal air and objects are kind of blue and the warmth of a living thing runs through reds to yellow and really hot stuff goes into white? Is this accurate?

And then there's Light Amplification/Night vision- normally done in green because the human eye can perceive green more easily?

How’s Infrared work?
I was watching some stuff on Animal Planet and they went down into some caves, Total absence of light! Pitch Black! And they were using infrared cameras to see. What they showed was basically all shades of grey (more or less) but you could make most stuff out pretty well.
They were looking at bats and bugs and some skunks and raccoons that would come in and somehow find stuff in the dark to eat. Pretty cool stuff!

Makes me think of "Darkvision” just to relate it to 'game stuff.'

Besides stuff for D&D this could be good to know for a modern setting of course since the technology is in use now!

 

[Arkhandus]

Have a look at this rant by Sean K. Reynolds, from his website. He recently discussed the Infravision mechanic of older D&D editions, which was the precursor of 3E Darkvision. Infravision was simply thermal sight, but Sean does a good job here of describing how it works and how impractical it really is for D&D. He gives some thermographic photos of what some stuff looks like in infrared as well.
http://www.seankreynolds.com/rpgfiles/rants/infravision.html

 

[rpgHQ]

Theres differing forms of infrared imaging. That show in the cave showig hte black and white images of animals is still thermal imagin, many security cameras use that same form of infrared imaging. A light source would show up as a big blob or bright spot, its basically a turned down form of thermal imaging so it looks crisper like you noted. The camera's not only pick up infrared lightwaves but sends out its own beam, not sure how it works but thats how most of those black and white night security camera's work. When you see those cop vid shows on TV and the heliocopter camera is able to pick up the badguys footprints and such is beause their using equipment that is more sensitive to infrared readings.

Since it is outside the spectum of light we can see, all those color infrared images you see are artifical, the equipment is designed to show the different levels of infrared frequencies as certain colors. Without the artificial color imaging you get black and white images. Thats kinda how it is with most images you see for things in outerspace(like from the hubble telescope), nebulas and galaxies and such, their touched up to show colors.

Creatures with infrared sensory (like pit vipers) I think its still debatable if its colored or black and white. Theres no way to know how their brain is interpreting the information.

Anyhow that camera in the cave showing the animals in the pitch dark is thermal, just implemented differently.

 

[paulewaug]

wow

Hey Guys!

Thanks!
Both of those posts were Very helpful!!

(And thanks to Sean, of course, for his rant!! )

Wow he's even got a nice heat range chart on there, I mean granted it's from another sight I guess but still....

Man that is quite an article!
Kind of makes you think-
For one thing you can really take Darkvision for granted!
And it goes to show how you can't really try to make D&D Too realistic I guess!

I do think some of the questions he brings up about spells, and infrared in general, Could make for some fun gaming...
But are probably best saved for d20 Modern or something.

So things I liked in particular:

Gaseous Form: Can you see the gaseous person with infravision? A wandering hot zone of air?

I just found that to be funny! (Insert 'Ren and Stimpy' humor here)

While we're at it, if infravision is used, you'd need to note for each creature whether or not it gives off heat, and if it's a low, medium, or high level of heat (relating to the gelugon/ice devil question earlier).
-------------------------
Infravision has a fixed range (usually 60 ft.). This meats that a red dragon standing in the dark 70 ft. away from a dwarf cannot be seen by the dwarf, even though it should be putting out plenty of heat to reach into the dwarf's 60 ft. infravision range. To account for these effects, infravision would need rules to determine how far out a creature's heat signature extends beyond its body (suggestion: I'd add it's smallest face statistic in each direction as a rough guideline). Of course, that means that infravision is not longer a simple flat value -- more work for the DM.

It would be an interesting element to see an "Infrared radiates to 'this range' " attribute on all the MM entries.
But the last line sums it up for the most I guess.

But thanks again for the quick and useful info guys,
and for the heads up on the 'cave camera' rpgHQ !

 

[tarchon]

So the title kind of says it.

What do you guys know about actual night vision and in darkness?

There's Thermal Vision- this would be blobs of color right? Normal air and objects are kind of blue and the warmth of a living thing runs through reds to yellow and really hot stuff goes into white? Is this accurate?

Not exactly. The color you get in the imaging system is arbitrary "false color" since infrared light is invisible to the human eye. You can assign the colors to infrared wavelengths however you want. Basically, objects in normal environmental temperature ranges emit light in the mid to far infrared (MIR and FIR) and you can tell what their temperatures are by the ratio of wavelengths. The hotter an object, the shorter the peak emission wavelength gets. You can get pretty good contrast between objects of even very close temperatures, but the closer the temperatures, the slower, more expensive, and noisier the system gets.

And then there's Light Amplification/Night vision- normally done in green because the human eye can perceive green more easily?

Partly - it also has to do with issues in phosphor display technology.

 

[tarchon]

Have a look at this rant by Sean K. Reynolds, from his website. He recently discussed the Infravision mechanic of older D&D editions, which was the precursor of 3E Darkvision. Infravision was simply thermal sight, but Sean does a good job here of describing how it works and how impractical it really is for D&D. He gives some thermographic photos of what some stuff looks like in infrared as well.
http://www.seankreynolds.com/rpgfiles/rants/infravision.html

The big reason infravision is physically unlikely is that warm eyeballs emit infrared too, so warm-blooded organisms essentially would blind themselves with their own body heat. It should work fine for undead though. Some snakes use a very simple form of thermal radiation detection (since they have much lower body temperatures than their prey), but it doesn't form images.

 

[Steverooo]

Rebuttal

If infravision is sensitive enough to be able to identify facial features and such, then infravision must be sensitive enough to see tracks on the ground from a warm creature (as we established above). AD&D doesn't have any rules for how long it takes for these tracks to fade. It also doesn't have any rules for the difficulty of tracking in this manner.

Actually, there were... In the Dungeoneer's Survival Guide?

Now let's take a look at some spells and how infravision would affect them (or, if infravision exists, how these spells require answers on other aspects of the game rules).

Blur: Wouldn't infravision negate this spell? A person using infravision is used to looking at a creature with a blurring, shifting outline (since the creature's body is heating the air around it, which the infra-user can see), so they should have no miss chance, or at least a reduced miss chance.

Or alternately, users of Infravision take Blur penalties all the time?

Burning Hands: Does this (and other fire spells) negate infravision temporarily because it's so hot? Likewise, is an ice creature (like a gelugon, or ice devil) invisible to infravision because it doesn't give off heat?

More like it generates a dazzle attack, followed by a "fog cloud" effect, which quickly rises (as hot air is wont to).

Cone of Cold: If this spell drains heat, do creatures that have been hit by it become harder to see with infravision for a while?

No, easier. Hot or cold, they stand out from the background temperature. In the AD&D book with rules on this, they became "black". As they rewarm, however, they would pass through "grey" and back to red-orange-yellow. In a combat, it would be too quick to worry about missing, though... especially as rounds were one minute long, way back then!

Darkness: If darkness prevents infravision, it's keeping heat from flowing through the air. Shouldn't that give some benefit against fire attacks?

Normal darkness doesn't prevent Infravision, and neither does the spell. Of course, some Magic User would then just create Deeper Darkness, or somesuch to do the job...

Displacement: Shouldn't infravision negate this, too? Even if the target's radiating heat is displaced, the target is also heating the air and ground, which shouldn't be displaced.

Almost the same answer as above... Spell doesn't work on Infravision? New spell (with half the duration at the same level, or one level higher) which also works Infravisually...

Faerie Fire: Not so much of a 3E D&D problem as an AD&D problem. AD&D faerie fire outlined a subject in a glow, making them easier to hit. A creature being viewed with infravision is glowing and should therefore be easier to hit than one viewed with regular light.

Which cancels those blurry penalties quite nicely, eh?

Gaseous Form: Can you see the gaseous person with infravision? A wandering hot zone of air?

This (and below) depends. Since the body's entire molecular structure is being reformed, anyway, the heat could be "done away with" at the same time. The real question, to me, is: are the bodily processes stopped while Gaseous, Iron-Bodied, or "Stoned"? Since creatures turned to stone certainly have theirs stopped, I'd say no, no heat while in these forms. YMMV.

Heat Metal: Even if it's not enough to blind infravision, shouldn't this spell make the target easier to hit, since they'd be outlined in extra heat?

No, because being able to see them by their heat IS making them easier to hit, already, turning a basically invisible PC into a basically visible one. To "shine a light" on this question, if a Fighter in a field, on a sunny day, shines a bullseye lantern on his opponent, does he get a bonus to hit him?

Invisibility: Infravision breaks this spell. If a creature is invisible to infravision, then something must be either (a) preventing the heat from escaping your body or (b) rapidly cooling the body heat leaving your body so it's indistinguishable from the surrounding air.

If Invisibility works by "bending light around you", then the area upon which you stand should vanish, too... breaking the spell by making it useless, as well ("Shoot above where the floor just disappeared!"). If it, instead, shows the area right behind the invisible, then that should be MUCH easier to spot (especially on a colored tile floor, for instance)! If it works by absorbing the incident radiation, then, again, the temperature inside the area should rapidly heat up, until you're brewing in your own sauce... not to mention, you'd be BLACK!

If it works by some extraplanar means, then your body - and its heat energy - are "out of phase" with the real world, the light from this one can't reach you (and you'd be blind to light), and your IR can't reach anyone who is NOT invisible, and they can't see you, either (but invisibles can see each other, ala Frodo and the Nazgul).

So how can an invisible creature see? The same way as an Astral or Ethereal one can, by "piercing the veil" between theirs and the Prime Material Plane. (Just in case anyone was wondering!)

Of course, with this explanation, you couldn't affect much of anything, while you're invisible... Which might be a good thing!

If it's the first option, then the invisible creature will heat up over time and eventually succumb to heat exhaustion and die; it also should reduce the damage of spells like cone of cold which "drains heat," and keep you warm in arctic areas (since you're not losing heat to the cold air).
If it's the second option, shouldn't it be a transmutation spell instead of an illusion? And wouldn't the spell have to be very "smart" to recognize the different patterns of heat and cold around you? Basically the spell would have to being doing double duty, muting two entirely different types of radiation to compensate for the senses that detect those types. It's like asking a French horn player (a fairly complex instrument) to play the keyboard at the same time -- quite a lot of work for a 2nd-level spell.
Furthermore, it doesn't address the secondary effects of a warm body -- the heated air and solid objects it touches. Does invisibility affect the cloud of warm air? If doesn't, an infravision user should be able to see the warm outline of an invisible creature and therefor be able to locate it in some way. If invisibility does affect the cloud of warm air, does it affect the parts of the ground they touch? What about the weirdness of an invisible user holding a torch? The light is visible … is the heat visible? You're asking a lot out of a 2nd-level spell.

With the only explanation of invisibility that makes sense (to me, at least), none of these are a problem. Heat can't be seen, because it isn't there, hence, it affects no objects. Likewise, an inviso holding a torch now sheds light into whatever the "plane of invisibility" is, and not the PMP (Prime Material Plane).

This also explains why you appear when you attack: you can't affect objects on the PMP while off it, just like Ghosts have to manifest to attack. Improved Invisibility apparently allows you to manifest a doorway, and stab through it...

Iron Body: If you're "living iron," do you radiate heat? Or are you room temperature like an iron golem? Heck, does an iron golem generate heat? Its parts probably grind together at some extent, and friction creates heat (that's why rubbing your hands together in cold weather helps). While we're at it, if infravision is used, you'd need to note for each creature whether or not it gives off heat, and if it's a low, medium, or high level of heat (relating to the gelugon/ice devil question earlier).

If you're "living" iron, yes, since life generates heat. Cold blooded ones do, just not above the "background" level, so can't be "seen" by it. Undead and Constructs don't, either. Ice Devils appear dark. Most other creatures are "medium", but fiery ones are "high", and cold ones "low". It's not that tough to figure out.

Mirror Image: Since this spell is a figment, it cannot produce real effects. It can't make light, and therefore it can't make infrared light, which means that the mirror images don't show up in infravision -- the spell would never be used by drow or other dark-dwelling creatures that don't use light.

If THAT'S true, the spell's nerfed! Since it can't create anything, there's nothing there to reflect (and split) the light to make all those extra images! Okay, so throw the spell out! No? Well then, if the visible light can be split and reflected, why not the IR?

Otiluke's Spheres: Does infravision penetrate these spells? If so, at what threshhold does the spell stop allowing heat? Could you do a "low heat" spell that could still damage people through these force effects?

Since this is a whole passle of spells, I'll let them be... If light can pass, IR can pass. If lightning can't, fire-flame heat can't. Heat Metal might, but not Fireball, etc. That's a whole lot more than just IR!

Statue: Same issues as iron body.

Same answers as above.

Wall of Force: Same question as Otiluke's sphere spells: Is a creature on the other side invisible to infravision? It allows visible light but not damaging sorts of energy, but enough heat will damage someone.

Light passes through a Wall of Force? Does Searing Light? Can I use my Circlet of Blasting on'em?

==========================

I think Infravision could work, just fine, if it was put back into the system with the appropriate thought! It had its problems for two reasons: 1) That thought wasn't taken prior to its introduction, and 2) Mixing real-world science with Myth & Magic tends to produce strange results, and untimately results in admitting "No, there's probably no way to make this work... Nerf the spell!"!



Then again, I have no problem with Darkvision, either

 

[rpgHQ]

The big reason infravision is physically unlikely is that warm eyeballs emit infrared too, so warm-blooded organisms essentially would blind themselves with their own body heat. It should work fine for undead though. Some snakes use a very simple form of thermal radiation detection (since they have much lower body temperatures than their prey), but it doesn't form images.

some simple some not so simple, thats debatable about the snakes, pit vipers have two sensory organs for infrared detection, many scientists suggest they have 3d perception with it. And about forming images for most infrared using animals, how do you know what their brain interpretes that data as? its light waves, isnt that what our own eyeballs sense?

Also eyeballs warmth doesnt mean infrared wouldnt still work, I have a security camera outside my home that uses infrared for imaging in the dark but it also has a infrared emittor(sp?) and motion sensor right under the camera lens, doesnt seem to mess the image up or motion detection at all. Pretty sure the emittor has something to do with active infrared imaging, but I havent read up on active and passive infrared technology so I may be way off base.

 

[Tsyr]

I, for one, still use Infravision... to heck with what SKR's rant says. I've not had the problems he insists are so horrible with it... Mostly because I rely on common sense when I DM, something that 3.0 and 3.5 seem to try to sheild you from needing to do...

 

[rpgHQ]

about steverooo's comments on the sean k article. Being a living life form isnt the qualifier for giving off infrared heat. Ice like whats made in your fridges freezer gives off infrared waves. Atoms and molecules give off infrared wave lengths. Its only at absolute zero that infrared waves are no longer transmitted as atoms/molecules and such cease to have motion at that point. Infrared camera's can pick up clouds/fog in the sky just fine as well as snow and ice. So those gaseous forms and ice critters would be viewable just fine with infravision. Colored infrared pictures/images are blurry because its artifical coloring and how that coloring is being implemented to represent the various infrared wavelengths and the sensetivity to infrared waves of the device. My security camera shows people and animals and the clouds in the sky just fine and not blurry, the only things in the image thats blurry is when its showing the neighbors houselights, car lights, street lights and during the day the sun.