The Naked Scientists

The Naked Scientists Forum

Author Topic: Optical Illusions - Why does the pink spot turn green?  (Read 16051 times)

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Have fun looking at this but then please tell me why in fact the pink dot appears green ?






Stare at The + and Notice The Purple Dots Turn Green.
« Last Edit: 08/05/2007 11:10:03 by BenV »


 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #1 on: 19/04/2007 15:55:57 »
the green color you see is the negative/opposite form of the pink color. whenever you look at an image, It is kind of burned into your vision in it's negative form.  In a grey background, It is much easier to see.

It's still very cool to look at!
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #2 on: 19/04/2007 15:58:19 »
wait, on further inspection, it appears to turn green because it does, in fact turn green. for about 1 frame it flashes green.  I could tell this because I scrolled to the top, and the pic was only a pink dot at the top, but low and behold, It still turns green at the same interval.

but the above is what would explain it if it was not false.
 

Offline elegantlywasted

  • Hero Member
  • *****
  • Posts: 573
    • View Profile
    • Deviant Art
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #3 on: 19/04/2007 18:05:46 »
Yah, it works quite well when you aren't looking at an animation
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #4 on: 19/04/2007 19:38:35 »
Scienceguy, are you sure it waan't just the same illusion with just one dot?
I tried "prtscn" and pasting into paint a few times and I never caught the green dot.
Can someone who actually understands it look at the source code or something to see what's really happening?
Has anyone got a video camera with slow motion?
 

another_someone

  • Guest
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #5 on: 19/04/2007 19:55:15 »
Yes, science_guy is right.  I left 3 dots on the screen, and there was a clear direction in which you could see the green dot travel - I cannot see why that direction (clockwise) would exist if it was just random timing.
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #6 on: 19/04/2007 20:36:52 »
It's not random, the dots go on and off in sequence clockwise. The green after image follows them; what else could it do?
Since this is an optical ilusion it's unlikely that just looking at it will tell us much.
Can anyone write a program that does this without using green?
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #7 on: 19/04/2007 22:26:37 »
It's not random, the dots go on and off in sequence clockwise. The green after image follows them; what else could it do?
Since this is an optical ilusion it's unlikely that just looking at it will tell us much.
I think you are right. I made a lot of "snaps" of that image using the key "stamp" on the keyboard (and copying it in paint) and it always comes out a circle of pink dots but one. It's a very well done optical illusion with colours, the best I've ever seen!
Quote
Can anyone write a program that does this without using green?
What do you mean?
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #8 on: 23/04/2007 16:34:00 »
ha! just took a screen shot.

at the top three dots, you notice that there is a fine line between the pink and the green, which would'nt be true for pixelating, and I have a screenshot (I would post it, but where did that option go?) where it shows the top left dot gone, and about 2 millimeters of green starting to show up on the top dot.

This is not an optical illusion.
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #9 on: 23/04/2007 16:36:52 »
it is very hard to catch, though.
 

Offline tony6789

  • Neilep Level Member
  • ******
  • Posts: 1127
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #10 on: 23/04/2007 16:45:39 »
aww!!!! [:-'(]i cant see it it doenst work! [V]
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #11 on: 23/04/2007 21:17:43 »
What really puzzles me is that anyone would bother to fake this since the real illusion works quite well (It's often done with a green picture of an elephant).
"Can anyone write a program that does this without using green?

What do you mean?"

I mean is there anyone out there who can copy this idea by writing some sort of (OK this is where it becomes obvious that I'm not that 'net savvy) HTML or other code that really generates a set of red dots then makes one of them disapear, then reapear at the same time as the next one disapears?
ie can someone do what this picture puports to do?
 

another_someone

  • Guest
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #12 on: 24/04/2007 03:12:50 »
There is no way that raw HTML can be used for that.

The actual image displayed above is using an animated gif - the other options would be a java applet, or using flash animation.  Both of the latter two would require that the person viewing the image downloads an addon into his browser to see the Java or flash animation.
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #13 on: 24/04/2007 21:04:43 »
Thanks for the lesson; I think I will need some more lessons before I earn my living as a computer wizard.
Can anyone here provide an animated gif that does what that one says it does?
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #14 on: 25/04/2007 13:14:27 »
ha! just took a screen shot.
at the top three dots, you notice that there is a fine line between the pink and the green, which would'nt be true for pixelating, and I have a screenshot (I would post it, but where did that option go?) where it shows the top left dot gone, and about 2 millimeters of green starting to show up on the top dot.
This is not an optical illusion.
I think you're wrong. The green you see is just due to the negative post-image effect (optical illusion).
Look at this image and then analyze the pixel's colours with an image editor; or: enlarge very much the image and then hide the pink colour moving the window. You'll find that there aren't green pixels, only pink and grey.
« Last Edit: 25/04/2007 13:18:08 by lightarrow »
 

Offline daveshorts

  • Moderator
  • Neilep Level Member
  • *****
  • Posts: 2583
  • Physics, Experiments
    • View Profile
    • http://www.chaosscience.org.uk
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #15 on: 25/04/2007 13:18:00 »
Also if you cover the pink spots with your fingers you no longer see the green.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #16 on: 25/04/2007 13:19:18 »
Also if you cover the pink spots with your fingers you no longer see the green.
Exactly. (Much simpler indeed!)
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #17 on: 25/04/2007 13:27:32 »
at the top three dots, you notice that there is a fine line between the pink and the green, which would'nt be true for pixelating, and I have a screenshot (I would post it, but where did that option go?) where it shows the top left dot gone, and about 2 millimeters of green starting to show up on the top dot.
The instructions to post images are in here:
http://www.thenakedscientists.com/forum/index.php?topic=3458.0
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #18 on: 25/04/2007 15:43:59 »
I know how to post images, but the link thing wasn't on the posting options.  It confused me.

however, I see what you are doing, and I just have to say, WOW.  It fooled me for a while, even when it is still screen.

soooo... just refer to my first post at this topic:
Quote
the green color you see is the negative/opposite form of the pink color. whenever you look at an image, It is kind of burned into your vision in it's negative form.  In a grey background, It is much easier to see.

;D

edit: yay! 400 posts!
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #19 on: 25/04/2007 19:16:49 »
One screenshot without the green doesn't prove anything. One image captured with the green present completely changes the idea of what's going on.
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #20 on: 26/04/2007 15:44:00 »
I did capture an image with green present, but only because it was right next to pink:  The pink caused the green to appear to be next to it in an optical illusion.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #21 on: 27/04/2007 13:31:34 »
I did capture an image with green present, but only because it was right next to pink:  The pink caused the green to appear to be next to it in an optical illusion.
Yes. Look at this, for example:Then cover all the pink parts and compare the greys.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #22 on: 27/04/2007 14:16:35 »
I did capture an image with green present, but only because it was right next to pink:  The pink caused the green to appear to be next to it in an optical illusion.
Yes. Look at this, for example:Then cover all the pink parts and compare the greys.
In this one I have turned pink into green:


The effect (purple triangle inside of the green) is much less apparent, however; you have to enlarge the picture and/or look at it for a while, to see it.
I have tried with a lot of different colours and the more apparent effect is given just with pink dots.
« Last Edit: 27/04/2007 14:20:09 by lightarrow »
 

Offline science_guy

  • Hero Member
  • *****
  • Posts: 701
  • I'm right there... inside neilep's head!
    • View Profile
Re: Optical Illusions - Why does the pink spot turn green?
« Reply #23 on: 27/04/2007 15:42:57 »
very good print screen pushing! :)
 

The Naked Scientists Forum

Re: Optical Illusions - Why does the pink spot turn green?
« Reply #23 on: 27/04/2007 15:42:57 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums