# Does anyone know how the science behind this image? **URL:** \ **Category:** Factual Questions\ **Created:** [November 3, 2009, 10:33pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215 "2009-11-03T22:33:20Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![MatthewGerlach](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@MatthewGerlach](https://boards.straightdope.com/u/MatthewGerlach)\ **Post date:** [November 3, 2009, 10:33pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/1 "2009-11-03T22:33:20Z")
Look at [this image](http://i.imgur.com/CLvcc.gif) (black dot) for the time it says. After about 10 seconds, something very ‘cool’ will happen. Can anyone tell me the science behind how we see the colours? ---
**Author:** ![Superhal](https://avatars.discourse-cdn.com/v4/letter/s/b4bc9f/32.png) [@Superhal](https://boards.straightdope.com/u/Superhal)\ **Post date:** [November 3, 2009, 10:39pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/2 "2009-11-03T22:39:49Z")
Shrug. I saw the colors. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 3, 2009, 10:46pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/3 "2009-11-03T22:46:59Z")
The phenomenon is something like visual fatigue - your visual system has a sort of ‘white balance’ function, just like a video camera - this enables you to perceive a sheet of paper as white regardless whether it is illuminated by sunlight, incandescent lamps, which are yellow-orange, or fluorescent tubes, which may be greenish. Your colour perception is relative - and its adaptability, whilst useful in most normal situations, can be forced to draw the wrong conclusions. ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [November 3, 2009, 10:48pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/4 "2009-11-03T22:48:34Z")
[Wiki page on afterimages](http://en.wikipedia.org/wiki/Afterimage) ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [November 3, 2009, 11:34pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/5 "2009-11-03T23:34:15Z")
I thought for sure it was going to end up being a screamer… ---
**Author:** ![Mindfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindfield/32/19759_2.png) [@Mindfield](https://boards.straightdope.com/u/Mindfield)\ **Post date:** [November 4, 2009, 12:00am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/6 "2009-11-04T00:00:44Z")
The short version: You’re just seeing a colour afterimage superimposed on a positive black and white image. Afterimages appear in opposite, or complimentary colours, so when the image reverts to positive black and white, the afterimage superimposes itself on the real image and you see the colours as you’re supposed to. If the GIF didn’t loop so quickly you’d eventually see the colour drain away as the afterimage faded. ---
**Author:** ![Standup\_Karmic](https://avatars.discourse-cdn.com/v4/letter/s/ac91a4/32.png) [@Standup\_Karmic](https://boards.straightdope.com/u/Standup_Karmic)\ **Post date:** [November 4, 2009, 3:07am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/7 "2009-11-04T03:07:02Z")
How might one create this effect with Photoshop on any given image? ---
**Author:** ![Silophant](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Silophant](https://boards.straightdope.com/u/Silophant)\ **Post date:** [November 4, 2009, 3:34am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/8 "2009-11-04T03:34:26Z")
Go to the Image menu, then Adjustments, then Invert. Then you’ll have to make it an animated GIF and replace it with a B/W version. How you go about doing that, I have no idea. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [November 4, 2009, 3:40am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/9 "2009-11-04T03:40:12Z")
> [@jayjay](#): > > I thought for sure it was going to end up being a screamer… Ditto. I read a few of the replies before I clicked the link. ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [November 4, 2009, 3:45am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/10 "2009-11-04T03:45:01Z")
I clicked on the link and what I see is: a computer generated sort of false color image. And after the time elapses I see the computer replace the colored image with a clear black and white picture. There is no science going on about one picture being replaced by another picture. Try this: click on the link and let the false color image load. Then go take a pee and don’t even bother to look at the black dot. The picture still changes. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [November 4, 2009, 4:15am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/11 "2009-11-04T04:15:43Z")
> [@ghardester](#): > > I clicked on the link and what I see is: a computer generated sort of false color image. And after the time elapses I see the computer replace the colored image with a clear black and white picture. What’s supposed to happen if you actually stare at the dot, is that for a moment or so, the switched-to black and white picture is colored. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [November 4, 2009, 4:44am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/12 "2009-11-04T04:44:59Z")
> [@Standup\_Karmic](#): > > How might one create this effect with Photoshop on any given image? Image ==\> Adjustments ==\> Invert. ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [November 4, 2009, 4:55am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/13 "2009-11-04T04:55:17Z")
> [@MatthewGerlach](#): > > Look at [this image](http://i.imgur.com/CLvcc.gif) (black dot) for the time it says. After about 10 seconds, something very ‘cool’ will happen. Can anyone tell me the science behind how we see the colours? What appears to be a static image actually changes from the negative to a black and white when the counter reaches the end… When the background photo changes to black and white, the negative visual afterimage leaves colors superimposed. Because there is now an underlying black and white photo, a normally blurry after image is substantially sharpened and the photo appears to suddenly change from a negative to a positive. You’d get a similar effect by switching your gaze from a negative color image to a white sheet of paper but it would not be as brilliantly crisp because there’s no underlying black and white photo to get colored in. Neat effect. I loved it. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [November 4, 2009, 5:52am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/14 "2009-11-04T05:52:21Z")
> [@Chief\_Pedant](#): > > What appears to be a static image actually changes from the negative to a black and white when the counter reaches the end… There’s no way something with an animated status bar on it can appear to be a static image. Anyways, the effect is called an [afterimage effect](http://en.wikipedia.org/wiki/Afterimage_effect). It’s just superimposed on a black and white image, which makes the effect seem much more clear. Our perception of color is at a lower resolution than our perception of light-dark. ---
**Author:** ![Isamu](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Isamu](https://boards.straightdope.com/u/Isamu)\ **Post date:** [November 4, 2009, 7:12am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/15 "2009-11-04T07:12:10Z")
A slightly colored (and inverted) picture changes into a normal black and white image when the counter runs down to zero? Where’s the trick? ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [November 4, 2009, 8:22am UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/16 "2009-11-04T08:22:10Z")
> [@Isamu](#): > > A slightly colored (and inverted) picture changes into a normal black and white image when the counter runs down to zero? > > Where’s the trick? It’s not particularly well-designed. The text at the bottom encourages you to shift your gaze away from the dot when the picture changes to black and white, which ruins the effect. If you keep your gaze focused on the dot, you’ll see a color image of the scene instead of a black and white image. ---
**Author:** ![SunSandSuffering](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@SunSandSuffering](https://boards.straightdope.com/u/SunSandSuffering)\ **Post date:** [November 4, 2009, 12:19pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/17 "2009-11-04T12:19:58Z")
Here’s another example: [http://www.johnsadowski.com/big\_spanish\_castle.html](http://www.johnsadowski.com/big_spanish_castle.html) ---
**Author:** ![Crotalus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crotalus/32/41_2.png) [@Crotalus](https://boards.straightdope.com/u/Crotalus)\ **Post date:** [November 4, 2009, 1:21pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/18 "2009-11-04T13:21:33Z")
> [@The\_Hamster\_King](#): > > It’s not particularly well-designed. The text at the bottom encourages you to shift your gaze away from the dot when the picture changes to black and white, which ruins the effect. If you keep your gaze focused on the dot, you’ll see a color image of the scene instead of a black and white image. I would say it is very poorly designed. The status bar pretty much ruins it for a lot of people, because, as you say, it distracts. The trick, as others have said, is that the sharp black and white photo looks like a color photo for a few seconds after the switch, if you can concentrate on the dot rather than the status bar. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [November 4, 2009, 3:08pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/19 "2009-11-04T15:08:41Z")
> [@Crotalus](#): > > I would say it is very poorly designed. The status bar pretty much ruins it for a lot of people, because, as you say, it distracts. > > The trick, as others have said, is that the sharp black and white photo looks like a color photo for a few seconds after the switch, if you can concentrate on the dot rather than the status bar. In other words, if you follow the directions, it works just fine. I thought it was neat. ---
**Author:** ![Crotalus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crotalus/32/41_2.png) [@Crotalus](https://boards.straightdope.com/u/Crotalus)\ **Post date:** [November 4, 2009, 3:11pm UTC](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215/20 "2009-11-04T15:11:43Z")
> [@robby](#): > > In other words, if you follow the directions, it works just fine. > > I thought it was neat. I guess my problem with it was that my eyes would not stay focused on the dot because of the movement of the status bar. So I pretty much couldn’t follow the directions completely, and the first time I tried, the illusion didn’t happen at all. [Next page](https://boards.straightdope.com/t/does-anyone-know-how-the-science-behind-this-image/516215.md?page=2)