What would seeing UV light tell you ?

[bilateralrope]

I've got myself involved in a pen and paper RPG* where one of the character creation options was a cybernetic eye that could see UV light. Since the campaign has us working for a private detective agency, I felt that seeing things that other players couldn't would be useful and grabbed it. The problem is that I've got no idea what it would seeing UV would tell me, nor does the gm, and the rulebook only says that I can perceive the ultraviolet range of the light spectrum.

Does anyone have any ideas ?

*Specifically Blue Planet.

[Adam Reynolds]

UV lights are used in forensics to detect bodily fluids in combination with luminol. Several anti-forgery mechanisms use this. Money has a strip that shows its value when a UV light shines on it. This is also occasionally true with things like credit cards.

[Eternal_Freedom]

That only helps if you've got a UV lamp, whereas this just lets you see the UV spectrum, so it wouldn't let you see things you'd expect to see from tv detective shows like blood stains and...other fluids.

[bilateralrope]

UV lights are used in forensics to detect bodily fluids in combination with luminol. Several anti-forgery mechanisms use this. Money has a strip that shows its value when a UV light shines on it. This is also occasionally true with things like credit cards.

Those all involve UV light sources. Which I do not have.

[trekky0623]

People with Aphakia, a condition in which the eye has no lens, are reported to be able to see ultraviolet light. During World War II, UK military intelligence would recruit Aphakic people to watch for German UV signal lamps from submarines (Source).

Insects can see UV light, so flowers make use of this with patterns not visible to humans, but visible to pollenating insects. Birds can also see UV light, and they use this in their coloration to attract mates.

UV light is able to penetrate the skin deeper, so you should be able to see deep bruises or bite marks not visible to the naked eye. UV cameras have been used in this way to prosecute child abuse cases where bruises were not visible.

[trekky0623]

And as others have said, the UV light thing with crime scenes I do not thing would be helpful here: Those fluids are absorbing UV light and emitting visible light through florescence, whereas what would be helpful is things reflecting UV light.

EDIT: You'd probably be able to see through clothing though, for the same reason as the bruising stuff above. Maybe for seeing concealed weapons? Or perving...

[Eternal_Freedom]

On the other hand, if you had a UV torch/lamp on you, it should allow you to find your way through dark areas without making yourself obvious, like infrared goggles do, but being rarer people are less likely to expect it.

[Broomstick]

That only helps if you've got a UV lamp, whereas this just lets you see the UV spectrum, so it wouldn't let you see things you'd expect to see from tv detective shows like blood stains and...other fluids.

The sun is a "UV lamp", so you could see some of those things under daylight.

It should also allow you to see the sun through clouds, at least as a light source, so you might be able to stay better oriented on a cloudy day, at least outdoors.

[Eternal_Freedom]

I'd have to check, but IIRC a good chunk of UV gets blocked by the atmosphere (which is a good thing to avoid us all, y'know, dying). I suppose it might be enough to recognise things like blood stains etc, depends how good this UV seeing eye is.

[Broomstick]

There's enough UV getting by to cause sunburn and allow bees and other critters to navigate - I suppose it depends on the sensitivity of the UV vision as well.

[Isolder74]

Bees see UV pigments in flowers that show them where the nectar is located in the flowers. Given how some natural dyes used in clothing works it might possibly allow you to spot guys wearing camo in the background. Something I've learned from a friend who is colorblind is that before the 90's he could spot camo next to the greens of natural foliage.

[Darmalus]

Well, if you don't mind drawing on another game system for inspiration:

You can see ultraviolet light (UV).
Solar UV is present outdoors during
the day, even under cloud cover, but is
stopped by window glass or any solid
barrier (earth, stone, etc.). Fluorescent
lamps also emit UV. Provided UV is
present, you can make out more colors
than those with normal vision.
This helps you discern outlines; spot
trace quantities of dust, dyes, etc.; and
identify minerals and plants. You get
+2 to all Vision rolls made in the presence
of UV, as well as to all Forensics,
Observation, and Search rolls to spot
clues or hidden objects.

At night, a small amount of UV
reaches the ground from the stars.
This doesn’t let you see in the dark, but
it does let you ignore -2 in darkness
penalties (cumulative with Night
Vision). UV penetrates farther underwater
than visible light. This lets you
halve all vision penalties underwater
(but in total darkness, you are as blind
as anyone else).

The bolded part seems most useful.

[Sea Skimmer]

GRUPS is wrong. UVB rays are blocked by glass, but few of those get past the atmosphere in the first place. They are also a very narrow set of wavelengths. The broader UVA spectrum goes through even thick glass with some absorption. Most animal UV vision lies in the UVA region.

Also since UV rays penetrate foliage strongly it could actually become very hard to distinguish certain details humans are used to seeing in a natural environment. UV is good for spotting movement and certain chemicals, but the advantage overall would be mixed, you would not want it on all the time. This is one of the reasons why birds often fly into windows. They see UV really well but glass windows don't glint in the UV spectrum the way to do for visible light, and the visible part of their vision is very limited. The human eye actually has its own filter that blocks UVA out because it'd cause problems otherwise.

[Starglider]

Also since UV rays penetrate foliage strongly it could actually become very hard to distinguish certain details humans are used to seeing in a natural environment. UV is good for spotting movement and certain chemicals, but the advantage overall would be mixed, you would not want it on all the time. This is one of the reasons why birds often fly into windows. They see UV really well but glass windows don't glint in the UV spectrum the way to do for visible light, and the visible part of their vision is very limited. The human eye actually has its own filter that blocks UVA out because it'd cause problems otherwise.

Well, presumably the UV component is being mixed into one or all of the RGB colour channels, as training the brain to perceive a fifth type of vision receptor is probably impractical. So there will be some unavoidable interference with normal colour perception when it is enabled, but not to the extent that you´d miss major outlines and objects. Although if this is just one cybernetic eye and the other is normal, then presumably you could perceive normal RBG plus up to three alternate colour channels (e.g. UVA and two-colour IR) at the same time, at least in the convergence zone of your vision. Not sure how well the brain would adapt to that.

[Jub]

If this is just one cybernetic eye and the other is normal, then presumably you could perceive normal RBG plus up to three alternate colour channels (e.g. UVA and two-colour IR) at the same time, at least in the convergence zone of your vision. Not sure how well the brain would adapt to that.

If we assume that this setting has the technology to do so, could some of the issues be solved by offloading part of the integration onto a specially designed vision chip that helps sort the signals into something the brain can more easily deal with? Say stepping down the amount of work the brain does to something like matching a near-sighted eye and a far-sighted one into 20/20 vision.

[Starglider]

If we assume that this setting has the technology to do so, could some of the issues be solved by offloading part of the integration onto a specially designed vision chip that helps sort the signals into something the brain can more easily deal with? Say stepping down the amount of work the brain does to something like matching a near-sighted eye and a far-sighted one into 20/20 vision.

Theoretically, yes, but practically, this would be really hard. The reason is that the visual areas get more abstract, comlicated and individualised the higher up the chain you go. Wheras low level vision input can be achieved with a planar electrode array and some modest signal processing, interfacing to high level vision areas is going to require a large distributed brain-computer interface and advanced AI to configure and drive it for each indvidual user. In a Ghost in the Shell type setting where it is completely possible to replace 30, 50, 70% of the brain with computers and keep the remaining neural tissue functioning as before, e.g. with near-total mastery brain-computer interfacing, sure. This is on the high end of cyberpunk fiction tech levels though, and pretty much implies brain uploading and hence general AI as well.

[Jub]

Theoretically, yes, but practically, this would be really hard. The reason is that the visual areas get more abstract, comlicated and individualised the higher up the chain you go. Wheras low level vision input can be achieved with a planar electrode array and some modest signal processing, interfacing to high level vision areas is going to require a large distributed brain-computer interface and advanced AI to configure and drive it for each indvidual user. In a Ghost in the Shell type setting where it is completely possible to replace 30, 50, 70% of the brain with computers and keep the remaining neural tissue functioning as before, e.g. with near-total mastery brain-computer interfacing, sure. This is on the high end of cyberpunk fiction tech levels though, and pretty much implies brain uploading and hence general AI as well.

That's kind of what I figured based on my limited knowledge.

This is all IIRC, but I'm pretty sure just doing straight computer vision is one of the hurdles that certain robots are having issues getting over. Things like getting a machine to pick out something like a red-orange block against a red background with just a pair of cameras are pretty tough.

[Starglider]

This is all IIRC, but I'm pretty sure just doing straight computer vision is one of the hurdles that certain robots are having issues getting over. Things like getting a machine to pick out something like a red-orange block against a red background with just a pair of cameras are pretty tough.

The difficulty of doing that, while significant, is minor compared to the difficulty of getting the fact that you have detected a red-orange block of shape X in position Y into the parts of the brain responsible for object identification and scene mapping, in a way that fuses neatly with the existing abstract representations of visual perception at those levels. Recent brain mapping work is doing well on identifying the paths of information flow, but how the information is encoded into neuron firing patterns is very difficult to determine (and less generalisable across individuals) after the first couple of layers.

[Jub]

The difficulty of doing that, while significant, is minor compared to the difficulty of getting the fact that you have detected a red-orange block of shape X in position Y into the parts of the brain responsible for object identification and scene mapping, in a way that fuses neatly with the existing abstract representations of visual perception at those levels. Recent brain mapping work is doing well on identifying the paths of information flow, but how the information is encoded into neuron firing patterns is very difficult to determine (and less generalisable across individuals) after the first couple of layers.

Thanks for the explanation, I appreciate layman's terms breakdowns of things like this. I love the idea of AI development and mind-machine interface, but I just don't have the right combination of smarts and drive to get anywhere near the stage where I could follow the journals and keep up with these things on my own.

[Ziggy Stardust]

While I admire the dedication to realism, for the purposes of a role-playing game why not just hand-waive things a little and say that this cybernetic eye lets you see things like bodily fluids and all that? That was almost certainly the intention behind the inclusion of that ability in the game in the first place, given how common that brain-bug is. I mean, you're talking about a role-playing game that features humans who have been genetically engineered to have gills so they can breathe underwater, I don't think it would really break suspension of disbelief to just say that the cybernetic eye lets you see a seaman's semen or whatever.

[Simon_Jester]

It's still an interesting intellectual exercise to think about what a special super-ability might really let you do.

[bilateralrope]

While I admire the dedication to realism, for the purposes of a role-playing game why not just hand-waive things a little and say that this cybernetic eye lets you see things like bodily fluids and all that? That was almost certainly the intention behind the inclusion of that ability in the game in the first place, given how common that brain-bug is. I mean, you're talking about a role-playing game that features humans who have been genetically engineered to have gills so they can breathe underwater, I don't think it would really break suspension of disbelief to just say that the cybernetic eye lets you see a seaman's semen or whatever.

That's up to the GM, not me.

Another factor to consider is that getting to see UV was very cheap. Character creation let me take x modifications each of value y or less. A cybernetic eye with all the functions* cost less than y and the eye counts as a single modification. Meaning that taking the eye with all the options cost me the same as taking it with all the options except UV. Though buying one after character creation would cost more for each option.


*I haven't mentioned the other functions because what they do is easily understood.

[Lord of the Abyss]

Birds can see in ultraviolet, which lets them see various things humans can't. It lets them see animal droppings and where animals have "marked" territory, lets them see many insects easier, and they can see through various kinds of natural and artificial camouflage that doesn't mask ultraviolet.

[madd0ct0r]

I'd go with Lord of the abyss and assume that unless specifically designed to be UV camouflaged as well, you can basically see anything that would normally blend in to human colour perception.

Also lets you get clever with torches and pens and secret messages

[jwl]

When it comes to fluorescent stuff used for forensics, it would probably make things worse, because the reflected UV light alongside would cause glare that would make the fluorescing stuff harder to see.