Most of us are familiar with magenta — it’s a kind of purplish-red that exists between blue and red on color wheels (color wheels don’t accurately represent the physics of photons, but they represent the philosophical reality: color is a human construct that helps us interpret wavelengths to better understand our world).
The odd thing about color vision is that magenta (or pink) color is not in the spectrum of colors, meaning it cannot be generated by a single wavelength of light. Our brains interpret the color sensation of magenta/pink as ‘absence’ of green.
Our visual system can interpret colors and shades in surprising ways. This 3×3 Tic-Tac-Toe grid, for example, showcases how easily our perception of brightness can be fooled.
Do you notice anything unusual in the grid below?
Show / Hide the Trick
The looping animation below brings the illusion to life, revealing the trick in action. That large green square behind the grid isn’t actually uniform—it’s made up of alternating dark and light green squares.
Our visual system works like a “comparative computer”. In fact, we never see colors in isolation, as the appearance of any color is affected by the colors surrounding it. So, under certain conditions, colors that are identical may appear different, while colors that are different may look the same. In our visual system there is a mechanism that enhances the contrast of the outline of an object relative to its background: it is called “lateral inhibition”.
Thus, even small differences in brightness between adjacent zones, or objects, are deliberately increased by our visual system and the brain to better distinguish them. But something strange happens when the brightness boundaries of the color zones are concealed: the cues the brain needs to trigger the lateral inhibition no longer exist and consequently we become blind to variations in color brightness, as shown in the animated gif.
“Everything we see hides another thing;
we always want to see what is hidden by what we see.” – René Magritte
My book “Fantastic Optical Illusions” (ISBN: 178739235X) features all the best and most interesting illusion types: ambiguous and impossible figures, hidden objects, color and brightness effects, length, size and shape misperceptions, illusory moving patterns and image paradoxes.
This best-selling book has been first printed in 2004, since then I have made important updates on the latest discoveries in the world of perception, to be sure the book will continue to amaze both the young and the adult reader. Available from Amazon UK and Amazon USA.
I really enjoy communicate the mysteries behind the science of perception in a simple and clear manner with the use of instructive images.
We live in a “reallusive” world… Illusions are not totally unreal, because we feel them as they were real. Reality is also a kind of ‘illusion’. The outside world is mediated through our sense organs: vision, hearing, taste, touch and smell. All what we perceive and feel are just REPRESENTATIONS of reality, not the reality itself.
Children have a different way of looking at the world. So, writing and illustrating optical illusion books for kids is not an easy task, because they are less fooled by visual illusions than adults. This is due to the fact that brain’s capacity to consider the CONTEXT of visual scenes, and not just focus on SINGLE PARTS of scenes, develops very slowly.
My new work “Optical Illusions” will make you question: “is seeing believing?”… The brain is an amazing thing, but it doesn’t always get things right when it comes to sight. My book is here to explain why, with astounding images, baffling puzzles, and simple reveals.
In the example below, in the left column, you can see two apples—one green, one red—appearing as a single solid color with a black cross over them. Now, if we remove the thick black lines, each apple clearly appears divided into four quarters of different shades—even though they are exactly the same in both columns, with and without the black cross.
Here’s a trickier version: with the black grid in place, the large green square appears uniform. Take the grid away, and it turns into a full-on checkerboard…
This occurs because in our visual system there is a mechanism that enhances the contrast of the outline of an object relative to its background: it is called ‘lateral inhibition’. Thus, even small differences in brightness between adjacent zones or objects are deliberately increased by the brain to better distinguish them. So, when the brightness boundaries of the color zones are concealed, the cues the brain needs to trigger the lateral inhibition mechanism no longer exist and consequently we become “blind” to variations in color brightness. The illustrations above have been taken from my book “Drawing Optical Illusions” who was translated in many languages. The book is still available from Amazon.
This eye-catching, colorful book is designed to inspire those artists interested in optical illusions and as an invaluable reference tool for people who to wish to create them. In clear, easy steps, this book shows people how to design a range of original and classic optical illusions and even how to create their own personalized illusions.
“Reality is merely an illusion, albeit a very persistent one.”
— Albert Einstein
Everything you “see” depends strongly on the context and attention you give to it. The mind and the world you experience are inseparable, as it is your 3-pound brain that make the world meaningful. Seeing isn’t some kind of direct perception of reality. Actually, our bairns are cnostanlty itnerperting, correcting, and giving srtuctrue to the viusal ipnut form our eeys. If this were not the case, you would not see any colors (consider that all the beautiful colors you see don’t really exist), and you would probably see the world upside-down! Moreover, you would notice in your visual field a very large dot, called the “blind spot,” where the optical nerve enters the eye.
A Zen master said once: “If you pour water into a cup, water becomes the cup; if you fill a bottle with water, it becomes the bottle!” Likewise, the context shapes the appearance of the world surrounding you. Your brains work by comparing information and stimuli: contrasting colors, shapes, depth in a dynamic changing environment … that’s why perception is relative and not absolute. Continue Reading →
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