This is clever

[FarSideOfTheMoon]

!

http://www.didntyouhear.com/2007/11/19/faces-can-hide-anywhere/

[Lord Muck oGentry]

You can see the face also if you move your head to one side.

How's it done?

[bobdezon]

Its an illusion caused by your ability to distinguish minor colour change and "fill in the blanks" over distance. The face (John Lennon) is visable because the white stripes are infact two different colours. You think it is pure white but it is not. The pure white value of 255 is the highlight colour and the shadowed area is a colour value of 238. When you step back from the image you blend the colours together to make an overall image. When you see close er it is much harder to distinguish.

[SimonC]

Its an illusion caused by your ability to distinguish minor colour change and "fill in the blanks" over distance. The face (John Lennon) is visable because the white stripes are infact two different colours. You think it is pure white but it is not. The pure white value of 255 is the highlight colour and the shadowed area is a colour value of 238. When you step back from the image you blend the colours together to make an overall image. When you see close er it is much harder to distinguish.

Yep - what Bobdezon said. I had PhotoShop open when I saw this, so copied the image into a new window and checked with the eyedropper. Those white lines aren't quite as consistently white as they appear close up.

I would guess that it's hard to distinguish the more subtle shades of grey close to the monitor, when you tend to focus intensely on fewer lines and monitor-glare is more apparent. But as you step-back, and more lines come into focus, then it's easier to visually 'average out' the effect, and the face becomes visible.

I don't know if that makes sense, but I kinda know what I mean.

Kinda...:smiley: ( it's late! )

[Lord Muck oGentry]

bd and SC,

Thanks to both of you for your helpful comments.

However, I was thinking of something different. From a normal POV I could see some shading in the 'white' areas, so I wasn't entirely surprised to see an obvious image when I sat back a little ( as is suggested in the link). But I noticed also that I got a sharp image when I kept the same distance but moved my head a foot or so to the side. Is the explanation similar in both cases?

[SimonC]

I just tried the same and it works for me too. My only thought would be that it might be something to do with viewing the image stereoscopically as we look straight at the monitor, as opposed to predominantly with one eye as we turn away. Or maybe to do with the difference in length-of-focus between the eyes as the head is turned.

Beyond that vague idea, I really have no idea why it should work like this. Fascinating, isn't it? I hope that someone here with more expertise in this area can offer a full explanation. :smiley:

[Lord Muck oGentry]

Hmmm. Not sure about it, as I'm getting similar results using one eye at a time.

Need experts here.

[SimonC]

Right then, it's magic, let's email Randi! 50/50 split sound ok?:smiley: ;D;D

[Lord Muck oGentry]

Fair enough. But which of us has got paranormal powers? :smiley:

[Mulder]

I can see the face very easily from any distance. With one eye it less distinct though moving my head from side to side makes it more or less clear.

So the question then is: have I just got excellent eyesight OR am am I easily fooled by optical illusions? :undecided:

[FarSideOfTheMoon]

I can see the face very easily from any distance. With one eye it less distinct though moving my head from side to side makes it more or less clear.

So the question then is: have I just got excellent eyesight OR am am I easily fooled by optical illusions? :undecided:

Maybe it also depends on the quality of your screen as well?

I think once you know it is there, you can something is wrong with the white, even fairly close. But I guess for most people, a casual glance is not going to see anything.

[Cuddles]

bd and SC,

Thanks to both of you for your helpful comments.

However, I was thinking of something different. From a normal POV I could see some shading in the 'white' areas, so I wasn't entirely surprised to see an obvious image when I sat back a little ( as is suggested in the link). But I noticed also that I got a sharp image when I kept the same distance but moved my head a foot or so to the side. Is the explanation similar in both cases?

I suspect that is to do with the pixels appearing different at different angles. Everyone is familiar with the effect on early LCD screens where you can hardly see anything, or the screen looks all funny colours, when you view it at an angle. Newer screens are generally much better and have much wider usable viewing angles, but they are still far from perfect. Moving to the side will make the difference between the colours far more obvious than when you're in the centre, where the monitor is designed to look correct.

Having just tested with my monitor, this does seem to be the case. If you move backwards, the face is still sort of blurry. If you move as far to the side as you can while still being able to see a picture, the face appears to be a completely different colour from the rest of the picture.