Welcome to the home of optical illusions, visual deception, trompe l'oell, plus anything that makes you look twice.
What's new today on Optical Spy?
Here is a great picture of George Clooney, one of our favourite actors. But is there something strange about it? Have a good look before you click on the picture to see a close up.
This beautiful girl really has a stunning face. But all is not what it seems. Click on the picture to go through to the post where you can see her the right way up.
Remember that we regularly update our Gallery pages with new opticals and look forward to receiving some suggestions from you. Also, you can upload pictures over at our Contact page if you have anything you think we might be interested in.
Here is opticalspy spelt out from Google Earth. Click here to see it all.
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Hidden Beauty
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Three new images added to our Street Art Gallery
What's new in the Spy Blog? |
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The McCollough Effect
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The Ames Room
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Illusionism
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Reverse Perspective
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Troxler's Fading
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The McCollough effect is a phenomenon of human visual perception in which colorless gratings appear colored depending on the orientation of the gratings. It is an aftereffect requiring a period of induction to produce it........
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An Ames room is a distorted room that is used to create an optical illusion. Probably influenced by the writings of Hermann Helmholtz, it was invented by American ophthalmologist Adelbert Ames, Jr. in 1934, and constructed in the following year......
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Illusionism in art history means either the artistic tradition in which artists create a work of art that appears to share the physical space with the viewer or more broadly the attempt to represent physical appearances precisely – also called mimesis. The term realist .....
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Patrick Hughes (born 20 October 1939) is a British artist working in London. He is the creator of “reverse perspective”, an optical illusion on a 3-dimensional surface where the parts of the picture which seem farthest away are actually.........
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Troxler’s fading or Troxler’s effect is a phenomenon of visual perception. When one fixates a particular point, after about 20 seconds or so, a stimulus away from the fixation point, in peripheral vision, will fade away and disappear. The effect is enhanced ......
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Metamorphosis |
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Popular Opticals |
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The Human Brain |
Cliff Face |
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The Greatest Magic Trick in the World |
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The Shepard Tone |
A Shepard tone, named after Roger Shepard, Professor of Psychology at Stanford University, is a sound consisting of a superposition of sine waves separated by octaves. When played with the base pitch of the tone moving upwards or downwards, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that continually ascends or descends in pitch, yet which ultimately seems to get no higher or lower. It has been described as a “sonic barber’s pole”.
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Mirror Anamorphosis |
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Physiological illusions
Physiological illusions, such as the afterimages following bright lights, or adapting stimuli of excessively longer alternating patterns (contingent perceptual aftereffect), are presumed to be the effects on the eyes or brain of excessive stimulation or interaction with contextual or competing stimuli of a specific type—brightness, colour, position, tile, size, movement, etc. The theory is that a stimulus follows its individual dedicated neural path in the early stages of visual processing, and that intense or repetitive activity in that or interaction with active adjoining channels cause a physiological imbalance that alters perception.
The Hermann grid illusion is best explained using a biological approach. Lateral inhibition, where in the receptive field of the retina light and dark receptors compete with one another to become active. Once a receptor is active it inhibits adjacent receptors. This inhibition creates contrast, highlighting edges. In the Hermann grid illusion the gray spots appear at the intersection because of the inhibitory response which occurs as a result of the increased dark surround. |
The philosophy of illusion

Just like many other words often used in a different sense in spirituality the word "illusion" is used to denote different aspects in Hindu Philosophy (Maya). Many Monist philosophies clearly demarcate illusion from truth and falsehood. As per Hindu advaita philosophy, Illusion is something which is not true and not false. Whereas in general usage it is common to assume that illusion is false, Hindu philosophy makes a distinction between Maya (illusion) and falsehood. In terms of this philosophy maya is true in itself but it is not true in comparison with the truth. As per this philosophy, illusion is not the opposite of truth or reality. Based on these assumptions Vedas declare that the world as humans normally see is illusion (Maya). It does not mean the world is not real. The world is only so much real as the image of a person in a mirror. The world is not real/true when compared to the reality. But the world is also not false. Falsehood is something which does not exist. if we apply this philosophy to the above example, the illusion is not actually illusion but is false. This is because in general usage people tend to consider lllusion to be the same as falsehood. As per adishankar's a guru of monist teachings the world we think is not true but is an illusion (not true not false). The truth of the world is something which can only be experienced by removing the identity (ego).