Eye-tricks and Visual Illusions

Making Optical Illusions

2011-09-05T06:34:00.000-07:00

‘Reality is merely an illusion,
although a very persistent one’
Albert Einstein

As you certainly know, optical illusion is a particular style of art that plays tricks on our eyes and consequently baffles our perception. You might almost put the effect down to faulty vision, and in fact these visual tricks are sometimes used to assess the performance of the eye or the brain.

For centuries, visual illusions have been created by means of the ingenuity of the human brain and they have exerted an enduring fascination on the viewer. Since the arrival of the printing press and, later, film and digital imagery, millions of illusions have been produced in the name of art, science, education and, especially in the modern world, entertainment.

Creating a new optical illusion, or even reproducing one that already exists, may constitute a real challenge for your artistic skills, or it may simply represent an original and funny way to express your creativity. With the aid of my new book “Drawing Optical Illusions” and a little patience, you will be able to draw effective and powerful optical illusions in a reasonable amount of time.

This guide contains a collection of recent and ancient optical illusion effects, along with demonstrations and tips to inspire you to create your own work. The different optical illusions are organized by effects and applications, such as moving patterns, impossible or ambiguous figures, color effects and distortion effects, presented in a way that will make it easy for you to put them into practice.

The French painter Edgar Degas once said that art is not what you see, but what you make others see. Yet if any artwork is in itself already an illusion, then visual illusion pictures represent an art style that plays a game with our perception twice over. The illusionist artist has first to persuade the viewer that his or her depiction is real, though what the viewer sees is not the reality but a two-dimensional representation of it, made with the help of visual conventions and rules. At the very moment the viewer is going to be convinced, he or she falls into the perceptual trap of the second illusion, the real one created by the illusionist artist, plunging him or her into a state of cognitive hesitation and surprise. In fact, visual illusions are a kind of mental diversion – they capture the attention and are intriguing, challenging and fun as well. In other words, optical illusions force us to pause and question the nature of reality.

You can see and read some excerpts of my book here.

Mask of Love illusion

2011-05-17T00:29:00.000-07:00

Below is the optical illusion project we presented to public at the Gala of "2011 Best Illusion of the Year Contest" held at Philharmonic Center for the Arts in Naples, Florida. Actually, the pensive face in a Venetian mask holds an interesting secret. Can you figure it out?

Look at this mysterious Venetian mask. Do you notice something particular? What kind of emotions do its features express?

To see what is going on in the picture, just watch the video!

The Puzzle of Seeing

2009-09-29T03:02:00.000-07:00

by Gianni A. Sarcone (Curiopticals)

Our brain is an artist that paints the reality that surrounds us. It transforms energy into color; links distances, movement and form to create reality in 3D; interprets visual stimuli and compares them to memories... and sometimes, it makes mistakes!

Are the eyes an open door to the world, as poets say? Well, honestly, not really. The fact is, we see the world through a pair of tiny peepholes, the pupils of our eyes. Our brain functions as a highly creative ‘camera obscura’. The brain elaborates the visual stimuli we receive, transforming them into true artworks.

The German poet Novalis said that the eye is a ‘superficial’ organ. That is indeed partly true. I will even add that it is an external organ: the eye with which we see the world is a part of the world itself. As soon as we open the eye, whup, the world pops in it!

The eye is a humble and silent organ. It cannot ‘see’ itself, and is itself unnoticed in use. Moreover, unlike a camera, the eye ‘creates’ a field of vision without real edges. That seems paradoxical at first glance, that our field of vision is limited but does not have boundaries... There are no ‘blank’ zones outside of our visual field. Our brain simply cancels out those edges with a smooth fade-out effect.

***The way we see and the way animals see***
Light from a scene passes through the pupil and strikes the eye's retina where it is reproduced upside-down.		Here is how our brain visually 'translate' the perceptive stimuli from the eye.
Some animals see differently than we do. Cats are red/green color blind, and only perceive the blues and yellows of the landscape.		Seabirds' photoreceptors contain yellow oil droplets which help polarize light and improve distance vision, especially in hazy conditions.
Bulls have few retinal cones, and as a result, they have no color vision. Also, their vision is much less acute than ours.		Bees and butterflies can see colors that we can't see. Their range of color vision extends into the ultraviolet

In English, there are two essential families of words that we use to express the faculty and the act of seeing: 1) ‘sight’, ‘see’, and 2) ‘vision’, ‘view’. Looking at these words etymologically, it seems most probable that they originally came from words that meant, respectively, “to follow something with the eyes” (from the Indo-European *seqw-) and “to have learned” (from the Indo-European *weid-). This suggests that, for our ancestors, an image was something to shape with the eyes (follow with the eye), a form of information taken from the real world (learning through visual perception).

Unfortunately (or fortunately?), seeing isn’t some kind of direct perception of reality. Atcually, our bairns are cnostanlty itnerperting, corrceting and gviing srtuctrues to the viusal ipnut form our eeys (see footnote further below). If this were not the case, we wouldn’t see any colors, and we would probably see the world upside down! We would also notice in our visual field a very large dot, called the blind spot, where the optical nerve enters the eye.

Moreover, vision isn’t an innate process at all. It depends to a large extent on ability acquired through a long and laborious undertaking. We take the concept of vision for granted, but a person who is blind from birth who later in life gains the sense of sight takes many years to learn how to understand and organize the things that he now perceives.

The ability to see is a process far from banal, and far from being passive. When we look at a panorama, its colors take around 30 milliseconds to arrive at the ‘visual cortex’ within the posterior lobes of our brain (also known as ‘striate cortex’ or ‘V1’). The shapes of the scene, and the sensation of the distances – which involve depth and motion – are perceived shortly after, at approx. 70 milliseconds. During these tiny slices of time, the brain filters, analyzes, and interprets the various pieces of the visual puzzle, trying to assemble them into a coherent image. In other words, it is crafting the best and most useful scene possible from the raw image data that our eyes present to us.

I’ve always been fascinated and impressed by how people with partial or total visual sensory deficiencies interact with the world. We cannot talk about visual perception or optical illusions without mentioning the other side of the coin... To understand how these people ‘see’ without sight is to understand just how important our sense of sight is (sometimes we don’t do it justice or give it the importance it deserves) and how it collaborates and integrates with the other sense organs.

Have you ever asked yourself what it is, when we see, walk, speak, feel and touch all at the same time, that links our sight with the sense of touch or hearing? The reality is we actually see very little: only that on which we are concentrating, or which we find important. Man without the crutches of the other sense organs would truly be lost, because it is they which permit us, subconsciously, to go about our everyday lives. An experiment demonstrated how at times we are really ‘blind’ in the truest sense of the word. In this famous experiment on ‘inattentional blindness’, performed in 1999, Daniel Simons and Christopher Chabris asked people to watch a video clip and count the number of times one of two teams of basketball players took possession of the ball. Many people (around 40 percent) didn’t notice at all a man in a gorilla suit entering stage right, doing a jig in the centre of the screen and then leaving, stage left. The clip demonstrated how we don’t see what we don’t pay attention to, even when it’s in front of our eyes!

*Most probably your brain has automatically corrected the sentence in “actually, our brains are constantly interpreting, correcting and giving structure to the visual input from our eyes”. It’s amazing, isn’t it?

What color does it look to you?

2009-09-23T01:49:00.000-07:00

1 in 12 people have some sort of color blindness that makes them unable to distinguish certain colors or shades of colors from others. Color blindness is, however, an inaccurate term to describe a lack of perceptual sensitivity to certain colors; a more precise term is: Color Vision Deficiency (CVD). Color blindness is the most commonly used term though it is misleading if taken literally, because colorblind people CAN see colors, albeit they cannot make out the difference between some couples of complementary colors. Color vision deficiency is not related to visual acuity at all and is most commonly due to an inherited condition. Red/Green color vision deficiency is by far the most common form, about 99%, and causes problems in distinguishing reds and greens. There is no treatment for color vision deficiency, nor is it usually the cause of any significant disability.

The most commonly used test to detect color vision deficiencies is the Ishihara Color Test.

Your personal experiences of being a color blind
If you are a color blind person you may want to help us by answering the 2 questions listed below:
1) In your opinion, what bothers colorblind people most?
2) Tell us some annoying questions to ask a colorblind person...

Click on "post a comment" below to post your suggestion(s).

A Window on the World

2009-09-09T01:18:00.000-07:00

The human being is a sponge who absorbs the changes of the physical world surrounding him. Actually, if the physical world had been unchanging, we wouldn’t need to receive sensations on the world that surrounds us since all would be static and everything would definitely have its final place!

Our sense organs continuously check, then, the changes of our immediate environment to allow us to act and react in keeping with it. If we see a wall in front of us, for example, we won’t charge into it, of course, but try to avoid it! Our senses however detect only a part of the reality – the most useful for us - and translate it in an ‘analogical’ way. Yes, our senses work analogically... For instance, it’s difficult to consider a single color in a distinct way, but always in relation to others. The same red color will be perceived differently according to the content or the context where it lies within.

Every living being has a ‘repertoire’ of sense organs which is peculiar to him, with a particular predilection for one or two sense organs: the human being favors sight; the dog, smell; for bats, it's hearing… Concerning the color’s perception, animals do not all see in the same way because they aren’t perceptive to the same part of the luminous spectrum. Here are two extreme cases: insects, for example, see the ultraviolet rays, while on the other hand, some snakes can perceive infrared rays.

However, interpreting what our senses perceive is not an innate thing, our brain has to learn to decode the steady stream of sensorial information (the stimuli) in order to transform them into something ‘comprehensible’. People born blind that recover sight, do not immediately understand what they see and have to face up to a long period of rehabilitation and discouragement before getting accustomed to seeing like everybody else.

I’ve always been fascinated and impressed by how people with partial or total visual sensory deficiencies interact with the world. We cannot talk about visual perception or optical illusions without mentioning the other side of the coin. To understand how these people ‘see’ without sight, is to understand just how important our sense of sight is (unfortunately sometimes we don’t do it justice or give it the importance it deserves) and how it collaborates and integrates with the other sense organs. When we see, walk, speak, feel, and touch all at the same time what is it that links our sight with the sense of touch or hearing, have you ever asked yourself? The reality is we actually see very little: only that which we are concentrating on or find important. Man without the crutches of the other sense organs would truly be lost, because it is they that permit us, subconsciously, to go about our everyday lives. An experiment demonstrated how at times we are really ‘blind’ in the truest sense of the word. In this famous experiment on “inattentional blindness” performed in 1999, Daniel Simons and Christopher Chabris asked people to watch a video clip and count the times one of two teams of basketball players took possession of the ball. Many people (around 40 percent) didn’t notice at all a man in a gorilla suit entering stage right, doing a jig in the centre of the screen and then leaving, stage left. The clip demonstrated how we don’t see what we don't pay attention to, even when it is in front of our eyes!

The eyes are one of the panes of the window on the world, the other panes are called hearing, touch, smell, and taste. It is good therefore, that when one of these panes gets broken, it becomes replaced by one of the others that we have, and it is how we learn to see with our hands and move with our hearing...

Gianni A. Sarcone
Artist and Author of "Big Book of Optical Illusions"