Which panel is darker optical illusion

Escher, whose skilful and impossibly surreal artworks illustrate a dizzyingly complex universe of tessellated patterns and alternate realities. The midth century saw an explosion of interest in Optical Art throughout Europe and beyond; artists were increasingly drawn to the worlds of science, color and optics at a time when advances in computing, aerospace and television were being made.

By the s, Optical Art had emerged as an art movement in its own right, with artists including Bridget Riley, Victor Vasarely and Jesus Rafael Soto making daring experiments within the realms of optics, each with their own distinct languages of abstract geometry. Optical Art emerged in line with Kinetic Art, with both styles sharing fascinations with technology and movement, but Optical Art was more focussed on two-dimensional rather than three-dimensional art forms.

So, what exactly does Optical Art look like? Geometric patterns are an important component in much Optical Art, allowing artists to experiment with how complex arrangements of lines, colors and patterns can pulsate or swell off a flat surface. As influenced by the alternate realities of M. Escher, various Op artists of the s also played with repeat tessellated patterns, pulling or stretching them in daring new directions. The pioneering French painter Victor Vasarely made dazzling designs throughout the s and s that seem to expand outwards from flat surface outwards into the space beyond, as seen in Epoff, Flowing horizontal and vertical lines suggest rippling waves of movement, while subtle, flickering modulations in light create shimmering, dizzying visual effects, as seen in Progression, Polychrome, Movement has been a key feature of Optical Art since the s, with various artists exploring how to induce motion on a flat surface through dynamic arrangements of shape and color.

British artist Bridget Riley is one of the best-known — throughout the s and s she was fascinated with the striking optical effect of high contrast, black and white designs, exploring how swaying wavy lines and close, repeat patterns could invoke the rippling sensation of movement.

Her paintings were so visually powerful that they could cause swelling, warping, flashing, vibrations, or even unsteadiness, afterimages and fainting. Venezuelan artist Jesus Rafael Soto was also fascinated by the invocation of motion in art, experimenting with how intersecting shapes and lines could induce hazy, disorientating visual effects in both two- and three-dimensional forms.

In his series Spirales, , motion is created by overlapping concentric white circles over a series of black ones. Opposing black flattened ovals with white, tall oblongs cause friction and a radial bluras if the circles have begun to spin into motion. A study recently published in the journal JNeurosci looked at the Pinna-Brelstaff motion illusion. This is where thick lines arranged into circles appear to rotate when the person looking at them moves their head back and forth. Brain scans showed that people process the illusion in the same way as they would a moving object, and that there was a processing gap of 15 milliseconds by neurons in the area of the brain that is critical for picking up visual motion.

This is why the still image appeared to come to life. Another famous illusion was recently used by scientists to predict the viewers' age. The image, in which people either see an old or young woman, was created by cartoonist W. With the naked eye, the brighter of the two planets Venus appeared larger than Jupiter, but when viewed through a telescope, Jupiter was clearly larger.

Galileo believed the lens of the human eye caused this so-called "irradiation illusion. The visual system has two main channels: Neurons sensitive to light things are called "ON" neurons, whereas neurons sensitive to dark things are called "OFF" neurons. The researchers recorded from both types of neurons in the experiments. The scientists found that the OFF neurons responded in a predictable, linear way to the dark shapes on light backgrounds, meaning the more contrast between a dark and light object the more active those neurons.

But the ON neurons responded disproportionately to light shapes on dark backgrounds, meaning for the same amount of contrast they had a bigger response. The distortion of light-sensitive neurons finally provides an answer to Galileo's puzzle. Venus, a light object on a dark background, appears disproportionately larger than Jupiter, a more distant, and thus darker, object. The distorted vision turns out to very useful for humans, Alonso said, "because when you're in a very dark place, it allows you to see small amounts of light.

But during the day, more dark objects are visible, so it's better that these aren't distorted, Alonso said. The study's results suggest the distortion may actually occur at the level of photoreceptors, the light-sensitive cells in the eye itself, rather than deeper in the brain.

This contrasts with Galileo's view that the lens of the eye was somehow to blame for the illusion. Having a stronger response to light than dark may be important when a baby's vision is developing. During the first few weeks after a baby is born, its vision is blurry, which could result in the light-dark distortion.