Certain fantasy creatures are extremely sensitive to concentrated UV light. eg modern vampires. They either slowly or rapidly burn up in-front of you when exposed to direct sunlight or modern high techy UV-lightsources.

I am trying to figure out if these creatures sensitivity to UV could be used as a method of passively identifying them, in situations where they are not exposed or burning. Essentially, when not exposed to direct sunlight, do vampire bodies absorb/reflect UV differently to a human; which could then be detectable by modern science?

If my near-future military designed something similar to our current-day night vision goggles, they could then be adjusted to work for vampires. If I hand certain characters specialist goggles capable of viewing the UV spectrum, would these vampires jump out of the crowds as either noticeably more reflective bright points or absorptive blackholes? Without actually exposing the vampires to an active Blacklight. Or would they look the same as a typical human until exposed and then they would light up on the thermal infra-red spectrum?

enter image description here Image of a human artist with phosphorescent bodypaint under a blacklight...She is not a vampire. image source


  • I am aware that the original Dracula and other vampires were not hurt by sunlight and that this is a modern interpretation of the legend.
  • I'm not after the sparkly-kind vampires...unless I should be.


  • I know Vampires can have many weaknesses that I can utilize. For example, my vampiric creatures are not harmed by garlic or the sight of crucifixes but can be deterred by UV light and water, that for some asinine reason my characters may have decided needs to be blessed. They are not dead per se but I have trouble picking them up on the IR scanners as they have a very low resting body temp. IR may be useful for identifying cooler vampires in large crowds of normal humans, however IR is not helpful in picking out Vampires in more isolated situations where they may be creeping up to attack your outpost etc. They will more than likely light up on the IR spectrum when they are fully exposed to light. Hence, I am focussing my question on just how their body reacts to UV light.

  • I'm not too worried how they react to massive amount of direct sunlight. They combust and burn. The speed of the combustion has yet to be determined as I need to figure out the actual mechanism causing it. Do they absorb or reflect or do their bodies react no differently when not exposed to excess UV. What would that look like in a topical exposure situation (no excess UV). To avoid answers focussing on the wrong end of the reaction, I am focussing my question on how they would react in passive, non deadly exposure situations.

  • I am focussing on their bodies reaction and not so much on the technology itself to see them. I can handwave the tech around how the body mechanism works, but I won't turn away any pointers. I mentioned the tech ability to see them, as that is my reason for this question. To figure out if they will be pretty bright lights, depressing black death-shadows or worse, show no difference at all!

  • I am hoping to identify them from a distance without actually having to come into contact with them. I'm not scared or anything. HQ is the one insisting on this simple safety precaution.

  • $\begingroup$ How does the UV effect them? --Do they absorb more or does what they absorb have more effect? Does skin color mater to you or will the setting be homogeneous? --Humans have a wide range of UV absorption. $\endgroup$
    – user25818
    Commented May 1, 2018 at 21:42
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    $\begingroup$ "she is not a vampire" -- Are you sure about that, though? $\endgroup$
    – anon
    Commented May 2, 2018 at 1:41
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    $\begingroup$ Good to see someone knows the original Dracula didn't burn up in sunlight. He couldn't transform into bats, wolves or a red mist during the hours of daylight except for noon. The German movie Nosferatu introduced vampires destroyed by sunlight. Lovely picture. Almost wish she was a vampire. $\endgroup$
    – a4android
    Commented May 2, 2018 at 2:49
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    $\begingroup$ @NicHartley - She’s clearly weakened by sunlight - look at how it’s making her fall to the ground and burn up! $\endgroup$
    – Obie 2.0
    Commented May 2, 2018 at 4:16
  • $\begingroup$ @notstoreboughtdirt, the vampire skin colour is not an issue. I'm trying to figure out if they absorb or reflect UV and how that would look, so I can't answer that part :) i don't know if the reason why they burn up in direct sun is because the skin absorbed too much or the skin reflected as much as possible and then could not reflect anymore. I have a feeling the sparkly kind of vampire has a high reflectance ability. $\endgroup$ Commented May 2, 2018 at 6:56

4 Answers 4


So we can actually use science to help us out with this fantasy concept, believe it or not. This is what I mean: vamipirism was initially inspired by a variety of illnesses, most notably a genetic blood disease (erythropoietic protoporphyria). Individuals with this disease are sensitive to light because MORE UV is being absorbed in to the skin, hence causing more damage. This is due to the accumulation of protoporphyrin in the skin, so what you can do is have vampires possess an accumulation of a certain molecule in the skin that absorbs UV light rather than refracts it.

  • 2
    $\begingroup$ I will +1 in 4 hours for the IRL example. I could definitely handwave/invent some sort of passive UV goggles to take advantage of that! $\endgroup$ Commented May 1, 2018 at 19:43
  • $\begingroup$ Or you could even have scientists use some sort of assay that detects the accumulation of this molecule. $\endgroup$
    – ani ben
    Commented May 1, 2018 at 19:45
  • $\begingroup$ I could, but I don't think I will have many vampires volunteering up their blood/skin samples for those tests :) I'm looking for ways to pick out the vampires without them necessarily being aware of it :) $\endgroup$ Commented May 1, 2018 at 19:48
  • $\begingroup$ You could also attach small UV-torches to your goggles, in case the UV radiation in dark, closed rooms isn't enough to distinguish vampires from normal humans. $\endgroup$
    – Liquid
    Commented May 1, 2018 at 19:55
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    $\begingroup$ @Liquid has a good idea. Small UV LED emitters (with a filter so the visible-spectrum portion of the light is blocked) discreetly concealed in additional equipment could help spot vampires indoors or in other locations where there is little or no natural UV light. The output wouldn't be enough to irritate the vampire (except at extremely close range maybe), but normal humans would be illuminated brighter, while the vampires would appear shadowy. $\endgroup$
    – Doktor J
    Commented May 2, 2018 at 15:28

Vampires are fictional creatures. In the stories I have read some are sensitive to garlic, some to holy water (and were mocked by non christian influenced vampires for this), some to light, some to silver, some to wooden stakes.

To cut it short: it is your story, you are free to set up any reaction to UV light that suits your plot needs.

By the way, being non living creatures they would be "cold", so IR vision would not spot them from the background as it does with living beings.

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    $\begingroup$ thanks for the IR and "being dead" reminder. that helps for crowds (I think) but not for picking out a vampire in a more isolated situation. $\endgroup$ Commented May 1, 2018 at 19:46
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    $\begingroup$ @EveryBitHelps Assuming you vampires are cold, the temperature issue would be able to immediately and distinctly identify the vampire, unless the vampire was using something to specifically maintain a temperature similar to normal-human. Assuming that the vampire is the same temperature as the ambient background, just an IR detector would not detect them. However, overlaying an IR image on top of a visible light (or other frequency) image would make the fact that someone was a vampire quite distinct. This has been depicted in various vampire shows/movies. $\endgroup$
    – Makyen
    Commented May 2, 2018 at 3:58
  • $\begingroup$ But, as stated, it's your story. You should come at this from the POV of what you want to happen in your story and ask what's needed to make it work that way. $\endgroup$
    – Makyen
    Commented May 2, 2018 at 3:58
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    $\begingroup$ @Makyen If a Vampire's blood still circulates, then they just need one of those stick-on heat pack things for sore muscles etc. Usually last for about 8 hours or so... $\endgroup$ Commented May 2, 2018 at 8:08
  • $\begingroup$ @Chronocidal While I'm not sure that a single one of those would be sufficient, there are a variety of ways which temperature or UV absorption could be mitigated by the vampire. What's possible really depends on the story and the details. However, we don't have that information. Thus, it's better to reason from having the OP define what effects they want to have in the story and then determine how those are possible. $\endgroup$
    – Makyen
    Commented May 2, 2018 at 8:14

If homo inimicus vampirus were real, and were so radically sensitive to UV light as proposed, and if that were similar to the issues porphyriacs suffer due to excessive epidermal protoporphyrin, they would indeed appear significantly darker than homo sapiens when seen in UV light: moreover, you'd not need a strong UV source to show this effect assuming reasonable active signal processing in your nightstalker-vision goggles. More than likely there would be a visible mottling similar to advanced age sunspots, or possibly to the pattern of veins in the skin, showing areas of greater protoporphyrin density, which would also be visibly different than homo sapiens.

But bear in mind human skin already absorbs a whacking lot of UV, hence both the dark look of the model in the photo you posted and our need for sunscreen.

They also wouldn't necessarily be instantly aware of UV impingement if the level of UV light were low - IRL I knew a porpheriac who had a severe breakdown due to excessive light and temperature exposure, and it was not by any means an instant affair: she was exposed, and over several days was more exposed (all her choices) and during this became more and more irrational and irritable, resulting in a fugue state and obsessive behaviour, which then gave way to high risk / gambling behaviours, the consequences of which precipitated a divorce, and not long after this a complete breakdown and suicide. She experienced pain, fear, anger and severe irritability starting some hours after the exposure began.

You could choose to parse that in your fiction as giving rise to a supernaturally strong fight-or-flight cortisol / adrenaline response to major UV exposure, with pain/fear/anger, and that might add far more verisimilitude than the typical "burst into magical flames and ash out instantly" treatment.

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    $\begingroup$ "skin already absorbs a whacking lot of UV, hence [...] the dark look of the model in the photo" - that doesn't follow, does it? If I understand correctly, the photo was not taken with a UV sensitive camera. $\endgroup$
    – npostavs
    Commented May 1, 2018 at 23:49
  • $\begingroup$ @npostavs well said: looked like standard light camera and fluorescent dye with UV light $\endgroup$ Commented May 2, 2018 at 1:57
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    $\begingroup$ Here are a few links showing UV sensitive photography of people: in fact the result is super-spotty based on melanin concentrations, and so a super-UV absorbent skin would probably be very visible in contrast kolarivision.com/wp-content/uploads/2017/04/… dpreview.com/forums/post/54428575?image=0 $\endgroup$ Commented May 2, 2018 at 15:08

Seeing as the UV-light is something that is invisible to our naked eye and can't be seen because we haven't adapted to it, using goggles that pick it up would be a good idea. (erythropoietic protoporphyria) is a disease as said above, that causes our skin to absorb more UV-light than usual, if this is the case the goggles would not be able to pick up UV-light on vampires because they would be absorbing it more. If you see a square that is red, that's because it absorbed every color except red in the visible part of the light's spectrum. I would imagine that when your character looks through these glasses ordinary people would be visible but vampires would very little, or completely invisible.

Basically your character suspects someone is a vampire in a crowd of people.They put on the goggles, and if they can see everyone in that crowd except the person they are suspecting, that person is indeed a vampire.

(I'm not an expert and any experts are free to correct me if I'm wrong.)

Keep in mind if you add science to your story, you would have to explain how different stages of darkness affect your vampires. For example if they are in shade, but the place is still visible to the naked eye, light is reflected to that position (it's just less intense). That means that the UV-light is reflected there aswell. Will this make your vampires weaker, or will they burn but at a slower pace? If you're making the case that UV-light hurts your vampires this is something you should keep in mind. The only place were they would be safe is in a place with no or very little contact with sunlight.


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