Illusion or not?!

[wizard509]

I think there's a bit of red (actually, shades of red) in there that shows clearer the more you zoom out.

I disagree Boy to me GP's reply seems to make sense but I understand what you are saying.

[handrawn]

print it out and look at it close under strong natural light - no red

the brain is doing it's usual thing of interpreting what the eyes send it, and in this instance getting it wrong; optical illusion

[Boy]

I opened the image in XDP, zoomed in and saw variations of hints of red (and other colors) in the white vertical bars. With the eyedropper, I also checked the black bars and they also have hints of red (and other colors). I imagine this was done on purpose to create the effect of a red can.

[handrawn]

I just tried that and I can get no red values for H or S above zero and a V value of around 99.6% - if you did better be interested to see

personally I think that is artifact, since the black will not be pure black and therefore there will be red frequencies there in the mix 'bleeding out'

interestingly I also tried it in affinity photo which, like photoshop, samples the pixels on zoom so they stay artifact free - not a hint of red anywhere when zoomed right in...

[Boy]

Zooming in and just looking at it with the naked eye, I can see the slight color variations, especially in the white bars. Slowly zooming out, the white turns to pink and finally to red. Look at part of the thumb and some reflections on the foreground, they're also red.

[gwpriester]

Here's a larger version. I think the illusion might have something to do with the blue green colors reacting to the black.

Because otherwise, why would our brains not see the same thing if the image was black and white or grayscale?

[handrawn]

@boy

yes I can see very slight red - it is espcially clear in the affinity photo zoom because it is designed for photo editing in a way xara is not - both these screenshots are of the exact same file at the exact same pixel size



like I said this is artifact, it has nothing at all to do with the illusion, which is dependent on how the brain filters and decodes the colour frequencies it receives

so I was wrong to say there were not there in the affinity photo zoom, sorry... they are scant is all I can say in feeble excuse, and as far as I can tell only present near the green which would make sense as artifacts, the rest of the bars seem clear as day

[handrawn]

yep, obviously looked too far away from the green first time round



even if it were not artifact that would never be visible at zoom out

as a designer gary may have studied the way putting two colours together can alter the colour you see one as, or even both, as opposed to when they are seperate - this is really a special case of the same thing....

[DanFelix]

Possibly the high presence of cyan. I would like to see it without the cyan and see if the eye still perceives the red. I suspect that anyone who has never seen a Coke can would still see red due to the high presence of cyan. Cyan is created from B and G light, depleting those cones but not the red cones. You can see this effect when staring at a color and then looking at a neutral density image.

[Boy]

@boy

yes I can see very slight red - it is espcially clear in the affinity photo zoom because it is designed for photo editing in a way xara is not - both these screenshots are of the exact same file at the exact same pixel size



like I said this is artifact, it has nothing at all to do with the illusion, which is dependent on how the brain filters and decodes the colour frequencies it receives

so I was wrong to say there were not there in the affinity photo zoom, sorry... they are scant is all I can say in feeble excuse, and as far as I can tell only present near the green which would make sense as artifacts, the rest of the bars seem clear as day

How do you know it's just artifact?

I don't know how the effect of a red can has been created but I can imagine it has to do with the use of all these subtle color variation, the vertical bars and, as Gary suggests, the green color. However, I don't believe we see red only because our mind expects to see red because it's a Coke can (this aside from the fact that the brand also comes in silver and black cans).