This Is Your Brain, On Light

Lest anyone doubt the ability of lighting to manipulate our minds, here's a quick little illusion to scramble your brain. I read the full explanation on the YouTube page (you'll have to click 'show more' under the video there) and I think I understand it. Maybe.

But my brain is still a little scrambled by the fact that what looks like a shadow in the checkerboard isn't actually a shadow. It's a tone.


[BrussPup via Giz]


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OpenID sal-e said...

It is well known fact to any engineer trained to work with any visual system like TV. But there is more. The same think applies how we see the movement or color. You might find this TED presentation very interesting:

August 17, 2011 12:39 PM  
Blogger Benjamin Cahill said...

David, this is fake. The light to the left of the checkerboard is not actually casting the shadow (or only very little of it) in the video. The checkerboard is printed with the (not real) shadow on it, and the overhead light cancels out most of the 'real' shadow created by the side light.

If the shadow was actually real, moving the square would have caused it to become lighter (and it's brightness would have differed with the darker-looking square on top), because it would have been moving into the light. This is not so, showing that the shadow is 'fake', or printed.

I love the checker shadow illusion, but this video is very misleading...better to have a card with it that you can fold to show they are the same printed color.

August 17, 2011 12:55 PM  
OpenID chrisnemes said...

Ah, trying to trick fellow strobists, Mr. Hobby?
It's you who taught us to check the light sources by the shadows they cast.

The cylinder apparently casts a shadow from the light source on the left, but checkerboard's own shadow gives it ayway: there is no spoon.

The cylinder doesn't cast any real shadow on the checkerboard. It's printed.

But it's still fascinating to watch. :)

August 17, 2011 12:56 PM  
Blogger Jon M said...

The "shadow" is the illusion as it's not actually there. It's printed on the paper. There's some trickery going on there, it's not just the light.

August 17, 2011 1:26 PM  
Blogger ed pingol said...

but, will it blend?


August 17, 2011 1:32 PM  
Blogger Dean said...

I first saw this on an illusion site with a lot of other pictures and had fun sampling the colour of both squares and staring at it for ages, This takes that to a whole new level and scrambles your brain.

August 17, 2011 1:35 PM  
Blogger Andrew said...

So there actually is no shadow from the cylinder? The tiles are shaded to give the illusion of a shadow.

August 17, 2011 1:39 PM  
OpenID projectxo said...

Yin or Yang... it's all relative.

August 17, 2011 1:42 PM  
Blogger TheStudioEntrance said...

ouch. my brain hurts

August 17, 2011 1:50 PM  
Blogger TheStudioEntrance said...

Ouch. My brain hurts. But I think I'm going to start moving things WITH their shadow all the time. Cause now I know you can just do that.

August 17, 2011 1:51 PM  
Blogger Carlos Bruno said...

Ahhhh ... EASY explanation ...
YOU is the one to not take DRUGS enough ... ;)

August 17, 2011 2:31 PM  
OpenID zoomicon said...

very nice! can also add a followup video part with the proof:

August 17, 2011 3:30 PM  
Blogger editwizard said...

It's not fake - if I understand it properly, there's a shadow printed on those squares going across the diagonal. Also, I think there is a real shadow too but it's not as dark as the 'painted' shadow.

Either way, the colors are very very close when sampled with pshop color-picker. Try it.

August 17, 2011 4:21 PM  
Blogger Eric Duminil said...

This has been on my todo-list for a very long time.
I finally uploaded my version today!

The trick is to print a checkerboard that has less contrast than usual (darkish grey to lightish gray instead of black and white) and use some soft yet directional light source.
I used a reflective umbrella, but I suppose a softbox or a beauty dish would have given better results.

August 17, 2011 4:40 PM  
Blogger chuckcars said...

Yin or Yang, it's all reflective.

August 17, 2011 4:52 PM  
Blogger Nick Fletcher said...

The thing that's wrong here is the tones in the shadow area. If they were actually in shadow you'd expect them to "appear" darker than the areas that aren't in shadow. However if you look at the opening shot the tonality across the checkerboard is constant. Take a screen shot and mask out all the other tiles except for the two in question. All of a sudden they're not so different

August 17, 2011 7:21 PM  
Blogger Drew said...

But the whole point here is that the shadow is painted on.
It's to illustrate that one level of dark grey in full light can be the same level of light grey in shadow.
There's trickery involved to make it work on video, but if you take a screen grab (or set the whole thing up all proper-like and took a picture) and look at colour values of the squares in question, it checks out; they're pretty much the same.

August 17, 2011 10:43 PM  
Blogger heavydpj said...

NOT saying it's fake, but it would have been more bellievable if there hadn't been blips and cuts at 1:03 and 1:10.

August 17, 2011 11:05 PM  
Blogger jonnydonut said...

you just blew my mind!

August 18, 2011 5:40 AM  
Blogger Doug Sundseth said...

The illusion is one I've seen before, though quite well executed here.

What interests me more is deconstructing the light that they used to make it look as though the pillar is casting a shadow.

It looks like they used a key-ish light low on the left, aimed up to light the camera-left side of the pillar but not have differentiated light on the checkerboard. Then they used a fill-ish light high camera right to give fairly even light to the grid. (There's a fairly hot spot on the floor to camera right.

(I'm sure there's more lighting, but I think those are the primary effects lights.)

August 18, 2011 10:10 AM  
Blogger Mike said...

In case you doubt the video, click "show more" under the video then download and print the cool jpg the author made available. It is freaky to see it work when you're the one moving the square.

On the upside, I made a buck betting a coworker I could convince them the two squares were the same color.

August 18, 2011 12:59 PM  
Blogger Scot said...

Most of the posters so far have not gotten it. The squares ARE the same color, and the cylinder IS casting a shadow. The shadow is why we perceive that they are different colors, because our visual understanding is that if it's in shadow, it must be lighter and if it's in the light, it must be darker.

August 18, 2011 7:05 PM  
Blogger Unknown said...


If the grey squares are all the same color and the "white" square is really the same color as the grey, except it is in the shadow, why isn't the "white" square the same color as the "grey' squares around it?

August 18, 2011 9:48 PM  
Blogger Rob said...

My brain just imploded and there's a big black hole over my shoulders, or is it grey???

August 19, 2011 11:20 AM  
Blogger Sharon Campagna said...

Why doesn't the other gray square turn white?

August 21, 2011 9:56 AM  
Blogger Sharon Campagna said...

Why aren't the other gray squares that are in shadow white?

August 21, 2011 9:57 AM  
OpenID photohike said...

True, this is just an illusion. But the impressive video clip

August 21, 2011 1:28 PM  
Blogger Steve Salt said...

I'm still working on APPLICATION. What can I do with this information. I know pulling a model and light farther from the wall makes the white wall grey to black.

August 23, 2011 11:12 AM  
Blogger James said...

The shadow is drawn onto the surface. It's not 'fake', the video doesn't claim that the shadow is real, you assume it is. That's the illusion.

Look at the template linked to in the description:

See at the bottom left of the raised check surface you can see that the light on the right is casting a shadow. That means it's brighter than the light on the left. The cylinder's shadow doesn't exist, it's painted.

It's brilliant.

August 25, 2011 4:16 PM  
Blogger Tony said...

The whole point here is that we do not perceive absolute values, we only ever perceive relative values.

Which is how almost everything we do with lights, setting keys, shadows, and ambient - gives us the effect of huge tonal range even when there is little actual range (at least in the hands of a master!)

September 01, 2011 9:03 AM  
Blogger Tony said...

The whole point here is that we do not perceive absolute values, we only ever perceive relative values.

Which is how almost everything we do with lights, setting keys, shadows, and ambient - gives us the effect of huge tonal range even when there is little actual range (at least in the hands of a master!)

September 01, 2011 9:04 AM  
Blogger Trucktographer said...

My head hurts!

October 19, 2011 3:04 PM  

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