Mirror: https://i.imgur.com/3TU00N4.jpg
On my Mac's Dell LCD monitor, this image has a surprisingly intense 3D effect. The colored blocks appear to be floating in front of the blue and black background.
On my iPhone, the effect doesn't work at all, and it appears completely flat.
This is not simply a parallax or contextual effect - it feels as if I am looking at one of those lenticular 3D postcards.
What's going on?
It's called chromostereopsis - http://en.wikipedia.org/wiki/Chromostereopsis
I do, and moving that image around my field of view gives a mild 3D effect. I've always suspected that my poly carbonate lenses have strong chromatic aberration[0], with reds being separated outwards (blues inwards) when viewed towards the edge of my lenses.[1] When moving that image around, the red areas move more than the blues, so yeah, that's a fake 3D effect.
[0] https://en.wikipedia.org/wiki/Chromatic_aberration
[1] this is especially noticeable when I look at Microsoft's logo with the colored squares. I know that they are supposed to be equally spaced out, but they almost never look that way to me, especially when viewed in thumbnail form.
The iPhone might use less extreme wavelengths for the colors, or use LEDs that are less spectrally-pure.
Edit: like the user named Someone commented below, it looks like this phenomenon has a name - chromostereopsis.
Viewing on a 2017 5K iMac here; don't wear glasses (as others have mentioned eyewear impacting their perception)
I dunno how people stand optics with such high CA. CR-39 is much better optically and also a lot less expensive-- vendors shovel people into polycarbonate because they can charge more for it.
E.g. from zenni CR-39 lenses are 'free'! but you have to click a bunch of extra times to choose them.
The Gestalt Principles are from cognitive psychology, the part of psychology that deals, in part, with how we sense (eyes) and perceive (brain / mind) visual stimuli. Those principles are used a lot in interaction design, UX design, human-computer interaction, etc.
The specific Gestalt principle at work here is likely the "Figure / Ground" principle, also known as "background-foreground". Our brains are somewhat pre-wired to see things as either being in front or back of other things. There are some optical illusions that mess with our perception of foreground, e.g. Rubin's Vase[1].
The picture in question has the buildings in black, indicating they're silhouettes because the light source isn't hitting the walls directly. The blue of the background suggests some light coming from the night sky, illuminating things from the back. The brightly colored signs would provide their own light in the real-world context, and they have a high luminance value[2], i.e. high perceived value of lightness, as if giving off their own light.
To sum it up, it looks 3d because our brains have evolved in a three-dimensional world and have built-in functionality that helps us "fill in the blanks" in situations with incomplete information.
References:
[0]: https://www.interaction-design.org/literature/topics/gestalt...
1. The blue light is physically behind the others wavelength;
2. The blue is (much) more intense than other wavelengths.
Some background.
The LCD panel is a RGB filter in front of a white light.
White light is usually* made with a blue diode with some phosphor on top. The phosphor converts some (but not much) of the blue light into the rest of visible spectrum. Most of emitted light is the original blue from the diode.
Fun fact: The sun is also mostly blue. And there are white lights that are pretty much only blue, but we perceive as white (usually sold for vegetative growth of plants).
* In the past we used fluorescent tube. Quantum dot film are becoming common now (they have been used for a while, but are mainstream now because Rec. 2020). There are white diodes, but I haven't heard about them being used as backlight -- their CRI are pretty terrible, and they are expensive.
I speculate this happens because my eye is focusing on the checkerboard pattern on the back of the monitor itself, which is behind the lcd, and probably far enough behind it (several millimeters) that depth perception kicks in.
- object overlap: overlapping object is assumed to be in front of occluded object
- color: dark background is distant, back in space
- water-surface-like pattern at the bottom, with stripes getting smaller and closer together toward the top.
- some scale variance in some of the rectangular patterns: they are vaguely similar to each other, at different scales: the smaller scales look distant.
Very vivid.
The reason is the blue/red wavelength thing discussed herein. Pretty standard optical illusion. But the RGB values and shapes are configured to create a better demonstration of this than I have ever seen!
(Also yes, glasses)
