[Tiger Eaten]

This is something that's interested me for some while and I hoped might give some of you an effect to play with. This pic is a frame out of a motion test that I did a good while back. Nothing terribly interesting until I viewed this one frame as a still. Is it just me or does the area around the character's head play with your vision a bit? I find that there's a strange depth effect here akin to what you might get with a cheap hollogram picture effect. The light purple almost seems to be on the surface of the screen rather than part of it. Try inverting red and blue and the effect remains, even an invert does not completely shake it. Odd. I find myself wanting to look at my screen from different angles. Am I alone in this? Can anyone explain what's at work here? I would love to see the effect reproduced (enhanced?). I hope I'm not wasting your time here, thank you.



Greetings to all.

[LeChuck]

ohhh, thats nice. But I dont see this "hologram" effect.
I like the mood that the blue creates.

[Sergenth]

Also. because that is the only non-blue color in the picture, your attention grabs it much more, but that doesn't account for the "warms come out, cools recede rule" which is what is supplying most of the effect.

Your monitor may have higher contrast than mine, maybe that accounts for it too.

On Gameboy Color games like Pokemon, I get a fake 3d effect when the sprites move across the screen, as if the sprite were slightly in front of it. I think it's motion blur from the background tiles that create this effect (fake depth). This effect depends on the amount of light hitting the screen and how close I am to the screen.

[Tiger Eaten]

CapnPyro: Ah, ok! That makes sense, I did a little reading just now about color use and it mentioned the same thing you did about colors grabbing your attention depending on their shade. Ah, so much to learn.

Sergenth: Yes you right that is the only dab of non blue. I must have a very simple mind. Oh, look at the pretty colors! My monitor is a viewsonic p815 21 inch, I think it handles color pretty well so mabey it's hitting me a little harder........NAH, it's my small brain.

Thanks you guys! Everyday somebody wakes up and think's they've found something new. And every night that same person goes to bed a little more humble.


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ROAR! CHOMP! MUNCH! (You've been tiger eaten!)

[[Shizo]]

pass

[This message has been edited by [Shizo] (edited November 17, 2000).]

[CyberArtist]

The effect you're experiencing is two fold. First off, the red on blue makes the red look as though it's comming forward more than the blue since we see warmer colors as being closer than colder colors. The other effect you might be noticing is once I realized happened on my old 15" NEC monitor. Close inspection of the screen and some experiments made me realize that the red color really IS closer to you than the blue, or at least there's another optical illusion happening here where the way te red and blue colors refract through the mesh cause the colors to appear to float above the screen more so than they really are.



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-CyberA(rtist) aka Ben Golus

Cyber...

[[Shizo]]

Is he talking about that pink glowing spit that comes out of his face and shaped like a diamond? heheh.

[AliasMoze]

Holy crap! I almost had to duck when I saw that thing flying out at me!!!!!

I'm being sarcastic, of course. Seriously, I don't see it. Of course, I have trouble seeing those magic eye things too.

[jcterminal]

also remember, that due to the physiology of the cones and receptors in the back of the human eye, if you put a vibrant red hue up against a vibrant blue hue, grey patterns form along the edge. sometimes this causes colours and shapes to seem to 'vibrate' near each other.

this could be a part of the strange feeling you get when you look at it.

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[Tiger Eaten]

hehehe....maybe I need my vision checked? Perhaps hologram isn't the right word or is misleading. I certainly don't mean the entire pic just a small part, I'm not expecting anyone to say "OH MY GOD, IT'S LIKE I COULD WALK DOWN THAT HALL! I'M THERE! I'M RIGHT THERE!"

No.

Just around the character's head, shizo is quite right, it's the...err..."glowing spit part" that I'm talking about. Well put Shizo. I dug up another frame that is perhaps a little more focused on what I'm talking about. Of course this whole thing could all just be a nasty combination of caffine and lack of sleep. Thanks for the looks.



LeChuck: Thank you sir!

[CapnPyro]

cools appear to recede (the hallway), and warms appear to be brought forward (glowing spit head). mix that with the sharp perspective of the hall and you have a nice 3d effect. i think the caffeine and lack of sleep are accounting for the rest..

-Capn

[JayBee]

I actually know EXACLTY what you mean here.

Do you wear glasses? This is a documented effect due to interference patterns, and is intensified if you wear glasses. If not you can still see it.

The intereference thing is also part of the reason for the "cools recede" rule, though that's also atmospheric.

So what's causing it? It IS to do with the way the eyes interpret light, but not so much to do with the cones and rods thing. It's actually a lens property that anyone who's seen a diffraction experiment before will know about.

What happens is that, as light enters a lens, the light is bent by a different amount depending on its wavelength. Red has a the longest wavelength, so is bent the least. Blue has the shortest, so is bent most.

What happens in your eye is that the blue and red are bent so differently that the eye sees a "gap" between the edges, which it can only get rid of by refocussing. The thing is, the human brain uses refocussing to give it depth cues, so interprets this change in focus as a change in depth. The reason it looks weird is that the brain also uses parallax (the overlaying of two images) to judge depth, and this is sending different information - it's saying that the gap between blue and red looks the same FOR BOTH EYES, which doesn't make sense unless the objects are at the same depth.

So, shouldn't the two cancel out? Not really, becuase the brain weights Focus more than Parallax. This is so that one eye can still judge distance, though not as well as two.

The "cools recede" rule is partly a result of this. The reason it's noticable here is that you have two extremes of wavelength, so the distortion is more pronounced.

Finally, if you doubt this effect, get hold of a book cover or something that has pure red text on a pure blue background. Stare at it, relax your eyes a bit, and shake it a little.

Once you've stopped throwing up, marvel at the wonders of optics

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. . : : j a y b e e

www.sketchboard.co.uk


[This message has been edited by JayBee (edited November 18, 2000).]

[This message has been edited by JayBee (edited November 18, 2000).]

[Tiger Eaten]

CyberArtist: I think you are right, with this viewsonic monitor, it really does seem like the red/purple is raised some. Some of it has got to be a brain thing but I think I'm picking up on something visual as well. I work in quite a dark room, so perhaps that intensifies things somewhat?

jcterminal: I didn't know that, I should have studied psych a little harder when I had the chance.


JayBee: Ah! Glad to have someone understand what I'm seeing. Perhaps it's a Scottish thing, as my father comes from your fair city? I ran a bit of a test after your advice about the book cover, a quick pick of red on a blue background and yes! While I didn't quite throw up (yay!) I've found some similar (disturbing) results. Seems like everyone's advice here is right on the money. Thank you for such a detailed explanation!

Keeping all of this info in mind, don't you think this is kind of an interesting field for exploration? Imagine if you actually got a solid hold on what causes what in the human perception and were able to harness that power in art? Beyond the typical tricks of sight and into an area where you could really start to tweak the human brain with fx's designed to produce a reaction? Err...I think I'm babbling..so I'll stop now.


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ROAR! CHOMP! MUNCH! (You've been tiger eaten!)