# Do any humans have the ability to see into the infrared or ultraviolet spectrum? **URL:** \ **Category:** Factual Questions\ **Created:** [October 19, 2009, 7:02am UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298 "2009-10-19T07:02:54Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Alex\_Dubinsky](https://avatars.discourse-cdn.com/v4/letter/a/dbc845/32.png) [@Alex\_Dubinsky](https://boards.straightdope.com/u/Alex_Dubinsky)\ **Post date:** [October 21, 2009, 10:43pm UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/21 "2009-10-21T22:43:31Z")
> [@Frylock](#): > > The before/after pics look suspiciously… purple… which might be expected since the filters involved are red and blue. A red filter + a blue filter in theory produces black. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 21, 2009, 11:17pm UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/22 "2009-10-21T23:17:13Z")
> [@Alex\_Dubinsky](#): > > A red filter + a blue filter in theory produces black. Well in the pictures, I can see reddish tones, and I can see bluish tones. That’s the basic reason I’m asking for confirmation. ---
**Author:** ![Alex\_Dubinsky](https://avatars.discourse-cdn.com/v4/letter/a/dbc845/32.png) [@Alex\_Dubinsky](https://boards.straightdope.com/u/Alex_Dubinsky)\ **Post date:** [October 21, 2009, 11:29pm UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/23 "2009-10-21T23:29:41Z")
> [@Frylock](#): > > Well in the pictures, I can see reddish tones, and I can see bluish tones. That’s the basic reason I’m asking for confirmation. Oh, look. I’ve found the flickr artist discussing his post-processing procedure: [bar exam: civil procedure | 0 IR original 1 auto level 2 swa… | Flickr](http://www.flickr.com/photos/zachstern/704249967/in/set-72157594568419670/) The image starts out quite drab, and the color is added. And here is the description of how the goggles work: > [@](#): > > These IR goggles are simple: red filters block blue light, and blue filters block red… yet both colors of stagelight filters happen to pass the invisible IR light. If you stack up some blue and red filters, you get black. But it’s not QUITE black, since they only block the “visible light” which has wavelength shorter than 700 nanometers. Together the two filters create an IR-pass or “lowpass” color filter. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 22, 2009, 12:25am UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/24 "2009-10-22T00:25:36Z")
> [@Alex\_Dubinsky](#): > > Oh, look. I’ve found the flickr artist discussing his post-processing procedure: [bar exam: civil procedure | 0 IR original 1 auto level 2 swa… | Flickr](http://www.flickr.com/photos/zachstern/704249967/in/set-72157594568419670/) > > The image starts out quite drab, and the color is added. > > And here is the description of how the goggles work: I had read that as well, on the site. I wanted to know how that process could have produced the pictures he was showing me. At flickr, you’ve found what looks to be a decent explanation. Thanks! -Kris ---
**Author:** ![Uncertain](https://avatars.discourse-cdn.com/v4/letter/u/6a8cbe/32.png) [@Uncertain](https://boards.straightdope.com/u/Uncertain)\ **Post date:** [October 22, 2009, 1:56am UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/25 "2009-10-22T01:56:49Z")
I’ve always thought it would be great to have UV vision and go to Vegas and mark the cards with UV-absorbing ink. You could write the identity of the card on the back. Note: don’t actually do this; it would be illegal, and get you thrown into jail (or worse). ---
**Author:** ![wbeaty](https://avatars.discourse-cdn.com/v4/letter/w/439d5e/32.png) [@wbeaty](https://boards.straightdope.com/u/wbeaty)\ **Post date:** [October 22, 2009, 3:54am UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/26 "2009-10-22T03:54:29Z")
> [@Frylock](#): > > Well in the pictures, I can see reddish tones, and I can see bluish tones. That’s the basic reason I’m asking for confirmation. Ah, that’s because I shot those photos using a stack of five Congo Blue filters, but no red filter to remove the blue leakage. If you include one or two layers of Primary Red, then the image should appear purely red. (But also, some cheap webcams have crappy color filters, and will see infrared light as blue or cyan.) “Even better $10 IR goggles” use goggles with a flip-down lens. That way you can install the Congo Blue stack in the main goggles, then place the Primary Red in the flip-down lens. In low-light environments it helps to let in some visible blue (since a total lack of IR makes you temporarily blind.) ---
**Author:** ![Turek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/turek/32/18782_2.png) [@Turek](https://boards.straightdope.com/u/Turek)\ **Post date:** [October 22, 2009, 12:13pm UTC](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298/27 "2009-10-22T12:13:21Z")
> [@bordelond](#): > > I thought the night-vision filter on the camera detected infra-red light? It does. I mis-typed. [Previous page](https://boards.straightdope.com/t/do-any-humans-have-the-ability-to-see-into-the-infrared-or-ultraviolet-spectrum/514298.md?page=1)