# What physical/physiological changes would allow humans to see other spectra? **URL:** \ **Category:** Factual Questions\ **Created:** [January 5, 2008, 8:24pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428 "2008-01-05T20:24:42Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 1:19am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/21 "2008-01-07T01:19:51Z")
[QUOTE=Malienation] Keep in mind [this experiment](http://www.sciencedaily.com/releases/2007/03/070322160852.htm) in which mice (which have 2 types of cones) are given extended color vision of the type humans (which have 3 types of cones) have by injecting a human gene into a mouse’s chromosomes. Startlingly enough, the mice had no trouble taking advantage of their new color vision, and did not seemed particularly disoriented by what must have seemed an unusual development. Seems like something that could be done on humans. [/QUOTE] That’s amazing. The mice wake up after the procedure and everything looks different… :eek: Where’s **Mouse\_Maven** when you need her? ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [January 7, 2008, 1:25am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/22 "2008-01-07T01:25:31Z")
[QUOTE=Sunspace] **AskNott** , could you have had a UV-transparent lens put in? 16 different colour receptors? I am now jealous. [/QUOTE] AND detects polarized light! wow. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 1:55am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/23 "2008-01-07T01:55:25Z")
Ploughing through the links off that IR goggle page, I discovered this: [http://www.maxmax.com/](http://www.maxmax.com/) This outfit sells IR and UV inks! Cameras! Filters! There are inks that fluoresce in the visible when hit by IR, and inks that fluoresce in IR when hit by visible. They’ll modify your camera to see IR, and apparently some cameras are sensitive to UV as well! For example, there’s a [Sony HD camcorder](http://www.maxmax.com/hdr-hc5.htm) that has been modified: > [@](#): > > Externally, there are no visual changes. Internally, we have modified the optics so that the camera can see from 330nm to 1200nm versus a stock camera which can see from about 380nm to 750nm. 330 nm to around 400 nm is UV; 700 nm to 1200 nm is IR. When are we getting that IRGBU monitor again? Maybe I should hit the electronics stores at Matheson and Dixie and start buying multicoloured LEDs. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 7, 2008, 2:28am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/24 "2008-01-07T02:28:24Z")
[QUOTE=Sunspace] They’ll modify your camera to see IR [/QUOTE] Chances are pretty good that your [digital camera already sees IR:](http://www.apogeephoto.com/may2003/odell52003.shtml) > [@](#): > > Use the “TV remote test” to determine if your digital camera is sensitive to infrared light. Television remote controls use infrared light to turn the TV on and off and to change channels. Aim your TV remote control at the lens of your digital camera from a few inches away, push a button on your remote, and view the image on the LCD panel (not the optical viewfinder) of the camera. If you see a white flash of light coming from the TV remote on your camera’s LCD screen, you’ve just determined that your camera is infrared-sensitive. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 2:42am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/25 "2008-01-07T02:42:03Z")
[QUOTE=Squink] Chances are pretty good that your [digital camera already sees IR:](http://www.apogeephoto.com/may2003/odell52003.shtml) [/QUOTE] Well whadda you know. The iSight camera in my Mac is IR-sensitive. When I aim the remote that came with the computer at the camera and press a button, a purplish-white dot of illumination appears on the end of the remote as shown in the iChat video preview. 🙂 ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [January 7, 2008, 3:24am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/26 "2008-01-07T03:24:19Z")
There’s some range in the near IR that’s used for remotes. I think they could be anywhere from 800 to 960 nm or so. Note, also, that this is the near infrared, and not the thermal infrared where objects like people glow in their own radiation. You have to do things very differently to see that, and it’s more expensive. The near infrared is also thermal infrared for things that are hot but not hot enough for us to see glowing. For example, I think a soldering iron would probably glow enough in the near IR for modified cameras to see, or maybe even plain ones. Silicon photodetectors in general are pretty good into the near infrared, the 800’s or even 900’s I think. Since they generate so many electrons from every photons, and IR photons are less energetic, and therefore a watt of IR has more photons than does a watt of visible light, silicon photodetectors are actually more sensitive in the near IR than they are in the visible, on a signal per watt of light basis. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 3:47am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/27 "2008-01-07T03:47:31Z")
Obligatory link to the [LED Museum](http://ledmuseum.org/). Here are reviewed LEDs of every colour, including IR and UV. Their slogan is “We put the ‘die’ back in ‘diode’.”. Heh. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [January 7, 2008, 12:25pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/28 "2008-01-07T12:25:22Z")
Dangit, I can’t find the site to provide the link, but someone did the same thing as the guy with the infrared goggles, except with ultraviolet. He made his own goggles to filter out all but NUV and went walking around (with the other colors filtered out, you can see by UV pretty good), and made a second one for his camera and took pictures. I would think what would be most cool would be to not filter all the other colors _out_ but to tamp them down so as to equalize the visual input that actually gets to the retina (i.e., make up for the UV-opacity of the retina) — in other words, not to see how things look in UV but to see how things look in RGBU. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 3:45pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/29 "2008-01-07T15:45:24Z")
[QUOTE=AHunter3] Dangit, I can’t find the site to provide the link, but someone did the same thing as the guy with the infrared goggles, except with ultraviolet. He made his own goggles to filter out all but NUV and went walking around (with the other colors filtered out, you can see by UV pretty good), and made a second one for his camera and took pictures. I would think what would be most cool would be to not filter all the other colors _out_ but to tamp them down so as to equalize the visual input that actually gets to the retina (i.e., make up for the UV-opacity of the retina) — in other words, not to see how things look in UV but to see how things look in RGBU. [/QUOTE] Cool! This is what I was thinking about after I read the IR-goggle page. I wonder what the filters were? Hmm. Googling ‘UV goggles’ just brings up all kinds of pages for UV-_protective_ goggles. Kinda the opposite of what we’re looking for. ‘UV-pass’ gives better results. [This link](http://sci.tech-archive.net/Archive/sci.electronics.basics/2007-10/msg00009.html) mentions a dark violet “Woods glass” which apparently passes UV while blocking visible light. There’s also mention of [SPIE](http://spie.org/), an association devoted to the ‘study and advancement’ of light. There seem to be mentions of UV-pass filters for photography. Evidently I’m not the first person to look for this… Here’s a [lightbulb](http://www.lamptech.co.uk/Spec%20Sheets/Osram%20HQV80.htm) made of Woods glass which gives IR and UV _only_: > [@](#): > > This lamp is the type known as the Blacklight Mercury, having an outer bulb fabricated from what is known as Woods Glass. It is a soft glass type heavily doped with nickel oxide which renders it almost completely opaque to wavelengths of light at the centre of the visible spectrum, but it has a high transmission of ultra-violet and infra-red rays. The only visible wavelengths transmitted are those close to each end of the visible range, i.e. the violet and deep red. In addition, iron oxide impurities in the glass prevent the transmission of ultra-violet below about 320nm, so these lamps do not emit a significant amount of dangerous shortwave UV, and are completely safe to observe when lit provided the time of exposure is kept within reason. Vision may appear blurred but this is not harmful, it is simply due to fluorescence of the eye itself which can make focussing difficult! The UV output is almost monochromatic centred around the 365.5nm line. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 7, 2008, 4:05pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/30 "2008-01-07T16:05:08Z")
[QUOTE=Napier] There’s some range in the near IR that’s used for remotes. I think they could be anywhere from 800 to 960 nm or so. Note, also, that this is the near infrared, and not the thermal infrared where objects like people glow in their own radiation. You have to do things very differently to see that, and it’s more expensive. [/quote] Yes, we used a thermal-imaging camera when I was in architecture school. [Here’s one](http://www.maxmax.com/thermal_tir3.htm). In longwave IR (something like 10000 nm, or 10 um), people light up in the strangest places when they get embarassed. 😃 > [@Napier](#): > > The near infrared is also thermal infrared for things that are hot but not hot enough for us to see glowing. For example, I think a soldering iron would probably glow enough in the near IR for modified cameras to see, or maybe even plain ones. I’ll have to shut off the lights and aim my webcam at the electric elements on the stove… > [@Napier](#): > > Silicon photodetectors in general are pretty good into the near infrared, the 800’s or even 900’s I think. Since they generate so many electrons from every photons, and IR photons are less energetic, and therefore a watt of IR has more photons than does a watt of visible light, silicon photodetectors are actually more sensitive in the near IR than they are in the visible, on a signal per watt of light basis. ---
**Author:** ![AtomicDog](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@AtomicDog](https://boards.straightdope.com/u/AtomicDog)\ **Post date:** [January 7, 2008, 7:52pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/31 "2008-01-07T19:52:18Z")
For infrared, maybe with some plastic surgery and neural rewiring, a [pit organ](http://en.wikipedia.org/wiki/Infrared_sensing_in_snakes) could be developed. The problem would be to keep the body’s own warmth from overwhelming the pits. Snakes, naturally, don’t have this problem. Perhaps putting the pits on antenna stalks would be the solution. Hey! I just created an Andorian! ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [January 7, 2008, 8:56pm UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/32 "2008-01-07T20:56:58Z")
\>The problem would be to keep the body’s own warmth from overwhelming the pits. Snakes, naturally, don’t have this problem. I think the pits would sense thermal flux, whether it was positive or negative or neutral. You can sense radiant heat pretty well, for instance, with the back of your hand, though of course its shape and the indistinct spatial arrangement of your sensitivity don’t give you much directional sense. You don’t have to be cold to detect differences in thermal flux. Notice that people can use thermal cameras to detect things that are colder than they are, for example cold spots inside a house (the camera would be at room temperature and the window or the fireplace or whatever would be cooler than that). And snakes aren’t cold, anyway. They are “cold blooded”, but this misleading term means they have little or no regulation of their body temperature, not that their temperature isn’t elevated. Snake blood would be somewhat warm coming out of the snake. It’s a consequence of metabolism. Whatever calories the snake is consuming just laying still are pretty much going to come out as heat. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 8, 2008, 8:54am UTC](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428/33 "2008-01-08T08:54:41Z")
[QUOTE=AtomicDog] For infrared, maybe with some plastic surgery and neural rewiring, a [pit organ](http://en.wikipedia.org/wiki/Infrared_sensing_in_snakes) could be developed. The problem would be to keep the body’s own warmth from overwhelming the pits. Snakes, naturally, don’t have this problem. Perhaps putting the pits on antenna stalks would be the solution. Hey! I just created an Andorian! [/QUOTE] Mentioning that problem was why I opened this thread; I’ve idly speculated about this for years. Barring cheating by using cybernetics, I’d say a better solution would be mounting the infraeyes on the inner curve of horns; thick, convoluted ones. Antenna would be too flimsy; one could set the eyes where they would be protected by the curve of horns. The horns would have a convoluted outer surface, which would both dissipate heat, and if properly arranged serve the same function as bat’s faces and ears and shape sound for use in echolocation. [Previous page](https://boards.straightdope.com/t/what-physical-physiological-changes-would-allow-humans-to-see-other-spectra/432428.md?page=1)