Color Illusions

Chromatic Rainbow Illusion

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Chromatic Aberration Illusion

If you squint at this Chromatic Rainbow Illusion, you will see a rainbow like effect between the red and white lines due to chromatic aberration.

Chromatic aberration occurs when different colors of light refract at different angles, causing the image to appear blurred or distorted. In the case of this illusion, Chromatic aberration occurs when red lines are placed against a high-contrast white background, causing the viewer to perceive a rainbow-like effect along the edges of the red lines. This illusion is a result of the way our eyes perceive and process different colors of light.

If you are interested in learning more about the Chromatic Rainbow Illusion, scroll down to read more about it.

Chromatic Aberration Illusion


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What is the Chromatic Rainbow Illusion?

The chromatic aberration illusion occurs when different colors of light refract at different angles causing the image to appear blurred or distorted. In the image above, it occurs when red lines are placed against a high-contrast white background, causing the viewer to perceive a rainbow-like effect along the edges of the red lines. This illusion is a result of the way our eyes perceive and process different colors of light.

How does the Chromatic Rainbow Illusion Work?

The illusion works due to chromatic aberration, an optical phenomenon that occurs when different colors of light refract differently as they pass through a lens or other optical element. This causes the colors to focus at slightly different points, leading to blurred or distorted images.

To understand how chromatic aberration works, it’s important to first understand how light interacts with lenses. When light passes through a lens, it is refracted, or bent, as it changes speed. This refraction causes the light to converge, or come together, at a focal point.

However, different colors of light have different wavelengths, which means they bend at slightly different angles as they pass through a lens. This causes the different colors to focus at slightly different points, creating a blurred or distorted image with a rainbow-like halo around the edges.

Some Similar Illusions

Here are some other optical illusions similar to the Chromatic Rainbow Illusion that you might find interesting:

  1. This Chromatic Adaptation Illusion allows you to see a black and white image in full color.
  2. Chromostereopsis is an optical illusion that involves the perception of depth and three-dimensionality based on color information. It is caused by the differential refraction of light of different wavelengths, known as chromatic aberration, as it passes through a lens.
  3. The Bezold Effect is a phenomenon in color theory where a change in one color can cause the perception of the surrounding colors to change as well.
  4. Moiré patterns: These are patterns that appear when two overlapping patterns with slightly different frequencies or orientations are superimposed.
  5. Color Afterimages: After staring at a bright color for a period of time, you might see an image of that color when you look away.
  6. Stereograms: Stereograms use a combination of two images that are slightly offset from each other to create the illusion of depth.
  7. Binocular rivalry is a phenomenon that occurs when slightly different images are presented to each eye simultaneously.
  8. Troxler’s fading, is a phenomenon in which a stationary visual stimulus eventually disappears from perception, even though it is still present in the visual field.
  9. The Scintillating Grid Illusion, in which a grid of black and white squares appears to pulsate or “breathe” when viewed from the periphery of the image.
  10. Silencing is a visual phenomenon where objects that change in luminance, hue, size, or shape appear to stop changing when they move. They “freeze” in place.

Discovery of the Chromatic Rainbow Illusion

The phenomenon of chromatic aberration which underpins the Chromatic Rainbow Illusion was first described and analyzed by the English scientist Sir Isaac Newton in the 17th century. Newton conducted experiments with light passing through prisms and lenses, and he found that the different colors of light were bent at different angles as they passed through the prism or lens, causing them to focus at different points.

In his book “Opticks,” published in 1704, Newton presented his findings on chromatic aberration, along with his theory of light and color. He also proposed a solution to the problem by suggesting the use of lenses made of two different types of glass with different refractive indices.

Since then, many advancements have been made in the correction of chromatic aberration, with the development of specialized lenses and lens coatings that are designed to reduce or eliminate this optical aberration.


References and Resources

In addition to the Chromatic Rainbow Illusion, please check out our complete list of illusions.

Purple and Green Illusory Motion

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Purple and Green Illusory Motion

I just love this Cool Purple and Green Illusory Motion image. This is a completely static image. The combination of the unique shapes and shading create the illusion of motion.

If you are interested in learning more about how this Purple and Green Illusory Motion image, scroll down to read more about it.

Also check out these cool examples of illusory motion: Amazing Colorful Illusory Motion and Black and White Illusory Motion and Fun Circles Illusory Motion and Illusory Motion and Super Cool Illusory Motion

Purple and Green Illusory Motion


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What is Illusory Motion in the Purple and Green Illusory Motion Image?

Illusory motion is a type of optical illusion in which stationary images or patterns appear to be moving. This can occur in a variety of ways, such as through the use of patterns with alternating colors or shapes that create the illusion of motion, or by presenting a series of static images in rapid succession to create the perception of motion.

One well-known example of an illusory motion effect is the “rotating snakes” illusion, in which a series of static black-and-white shapes appear to be rotating in a continuous, fluid motion. This illusion is created by using patterns with specific shapes and contrasts that stimulate the brain’s motion-sensitive neurons and create the perception of movement, even though the image itself is not actually moving.

Other examples of illusory motion include the “scintillating grid” illusion, in which the intersections of a grid pattern appear to be flashing or moving, and the “phi phenomenon,” in which a series of static lights flashing in sequence create the illusion of motion.

Illusory motion can be a fascinating and captivating experience, and it has been the subject of much research in the fields of visual perception and neuroscience. Scientists continue to study the underlying mechanisms of illusory motion and other visual illusions in order to better understand how the brain processes visual information and creates our subjective experience of the world around us.

How does Illusory Motion Work?

Illusory motion is caused by the brain’s interpretation of visual information that is presented in a particular way. Different illusory motion effects may be created by different types of visual stimuli, but they all involve the brain perceiving motion where there is none.

One explanation for illusory motion is that it is caused by the brain’s motion-sensitive neurons responding to certain visual patterns or stimuli in a way that creates the perception of motion. These neurons, located in an area of the brain called the visual cortex, are responsible for processing information about motion and spatial relationships in the visual field. When presented with certain visual patterns or stimuli, these neurons can become activated in a way that creates the illusion of motion.

Another explanation is that illusory motion is a result of the brain’s tendency to fill in missing information in order to create a complete and coherent visual scene. When presented with incomplete or ambiguous visual information, the brain may “fill in the gaps” in a way that creates the perception of motion or movement.

In either case, illusory motion is a result of the brain’s complex processing of visual information, and it is influenced by a variety of factors, including the properties of the visual stimuli, the context in which they are presented, and individual differences in perception and interpretation.

Some Similar Illusions to the Purple and Green Illusory Motion

There are many different illusory motion illusions, each created by specific patterns or stimuli that trick the brain into perceiving motion where there is none. Here are some examples of illusory motion illusions:

  1. Rotating snakes illusion: This illusion consists of a pattern of overlapping circles and curves that create the perception of continuous motion, as if the image is rotating in a circular motion.
  2. Motion aftereffect illusion: This illusion occurs when a person views a moving stimulus for a prolonged period of time, and then looks at a stationary object. The stationary object will appear to be moving in the opposite direction of the original stimulus.
  3. Autokinetic effect: This illusion occurs when a stationary point of light is viewed in a dark room for a prolonged period of time. The light will appear to move or “drift” even though it is stationary.
  4. Peripheral drift illusion: This illusion consists of a pattern of intersecting circles and lines that create the perception of motion at the periphery of the visual field.
  5. Barber pole illusion: This illusion consists of a rotating spiral pattern of alternating red and white stripes, which create the perception of upward motion even though the pattern itself is rotating.
  6. Wagon wheel illusion: This illusion occurs when a wheel appears to be rotating in the opposite direction of its true motion, due to the interaction between the frequency of the spokes and the frame rate of the video camera.

These are just a few examples of the many illusory motion effects that have been discovered and studied by researchers in the field of visual perception. Each of these illusions demonstrates the brain’s remarkable ability to create the perception of motion and movement, even in the absence of actual movement.

Discovery of the Illusory Motion

Illusory motion has been known and studied by scientists and artists for centuries, but it is difficult to attribute its discovery or popularization to any single individual or group. The use of visual patterns and stimuli to create the illusion of motion has been explored in various forms of art, such as Op Art and Kinetic Art, and in scientific research on visual perception and neuroscience.

One of the earliest recorded examples of an illusory motion effect is the Zoetrope, a pre-cinematic device invented in the early 19th century that uses a sequence of static images to create the illusion of motion. Other early examples of illusory motion effects can be found in ancient Greek and Roman art, such as the use of mosaic patterns to create the impression of motion and depth.

In more recent times, scientists and artists have continued to explore and experiment with the use of visual illusions to create the perception of motion. Artists such as Bridget Riley and Victor Vasarely are known for their use of geometric patterns and shapes to create illusory motion effects, while scientists have used illusory motion as a tool for studying the brain’s processing of visual information.

Overall, illusory motion is a phenomenon that has been studied and appreciated by many different people throughout history, and it continues to inspire new forms of artistic and scientific exploration.


References and Resources Illusory Motion

In addition to this supercool Illusory Motion example, check out our complete list of illusions.

Cool Red and Black Scintillating Grid Illusion

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Red and Black scintillating grid illusion

This Cool Red and Black Scintillating Grid Illusion creates the illusion of light and dark dots appearing at the intersections of a grid of white lines on a gray background. The dots appear to flicker and change color depending where you focus your view.

If you are interested in learning more about the Scintillating Grid Illusion, scroll down to read more about it.

Red and Black scintillating grid illusion
White and Black scintillating grid illusion


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What is the Red and Black Scintillating Grid Illusion?

The scintillating grid illusion is an optical illusion that creates the illusion of light and dark dots appearing at the intersections of a grid of white lines on a gray background. The illusion is caused by the way the brain processes visual information.

When viewing the scintillating grid illusion, the brain tries to process the contrast between the dark dots and the light background. However, the brain also perceives the white lines as being brighter than the gray background, which creates a brighter area around the intersection of the lines. This makes the dark dots appear even darker and creates the illusion of light and dark dots appearing and disappearing at the intersections.

The scintillating grid illusion is an example of the Hermann grid illusion, which was discovered by the German physiologist Ludimar Hermann in 1870. The Hermann grid illusion works in a similar way, but instead of white lines, it uses black squares on a white background to create the illusion of gray dots at the intersections.

How does the Red and Black Scintillating Grid Illusion Work?

The Scintillating Grid Illusion is an optical illusion in which a grid of light gray or white lines on a dark background appears to flicker or “scintillate.” The effect is most pronounced when the observer is looking directly at the intersection of the lines, and it is caused by the way the visual system processes the edges of the lines. The illusion is often used to demonstrate the neural processes that underlie visual perception, and it is related to other optical illusions such as the Hermann grid illusion and the Mach bands illusion.

The Scintillating Grid Illusion is believed to work by the way the brain processes the edges of the lines in the grid. The visual system is sensitive to the contrast between light and dark areas, and the edges of the lines in the grid create a high contrast between the light lines and the dark background. This high contrast causes the visual system to enhance the edges, creating the illusion of flickering or scintillating.

It’s also thought that the mechanism behind this illusion is related to the way the visual system deals with the ambiguous edges of the lines. In the intersection of the lines, the brain receives information that is not clear, and it tries to fill in the missing information by creating the illusion of movement.

Additionally, the illusion is more pronounced when the observer is looking directly at the intersection of the lines, as opposed to looking at the lines themselves. This is likely due to the fact that the visual system is more sensitive to edges that are oriented perpendicular to the line of sight.

Some Similar Illusions

The Hermann Grid Illusion: This illusion is created by the way the brain perceives intersections of lines. When the intersections of a grid of lines are viewed, small gray dots appear at the intersections, even though they are not actually there.

Hermann Grid

The Bezold Effect: This illusion is created by placing two or more colors next to each other, and the way they appear to change when they are close to one another.  

Bezold_Effect

The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

Cafe Wall Illusion

Discovery of the Red and Black Scintillating Grid Illusion

The Scintillating Grid Illusion is a variant of the Hermann Grid Illusion named after Ludimar Hermann, a German physiologist, who first described it in 1870

Ludimar Hermann (1838-1914) was a German physiologist and psychologist who was best known for his work on the perception of visual images and the nature of visual illusion. He is most famous for his discovery of the Hermann grid illusion, which he described in 1870. It is a visual effect that occurs when viewing a pattern of light and dark lines crossing each other to form a grid, creating the appearance of gray spots at the intersections of the lines, even though the intersections are actually the same color as the background.

He studied medicine in Berlin, later he was a professor of physiology and neurology in Würzburg and Tübingen. He also worked on other aspects of visual perception, such as the perception of movement and the illusion of movement, as well as on the perception of sound and hearing. His ideas had a significant influence on the development of psychology and neuroscience. He was also an important figure in the history of neurology and psychiatry.


References and Resources

Check out our complete list of illusions.

Concave or Convex Illusion

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Concave or Convex Illusion

In this Concave or Convex Illusion the circles on the left all appear to be convex and all the circles on the right appear to be concave.

There is only one change in the circles that creates this effect. In all other ways, the circles are identical. The difference is in the shading. The circles on the left as light on top, while the circles on the right are light below.

If you are interested in learning more about this Concave or Convex Illusion, scroll down to read more about it.

Concave or Convex Illusion


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What is the Concave or Convex Illusion?

The concave-convex circle illusion is an optical illusion that makes it appear that two identical circles are different only by changing the way that they are shaded. In reality, the circle remains the same shape throughout the illusion.

The key is the shading a which creates a perceived change in curvature of the circles. It is a fascinating example of how our brain can be tricked by visual information and highlights the complexity of perception and interpretation of visual stimuli.

How does the Concave or Convex Illusion Work?

The concave-convex circle illusion works by taking advantage of the way our brains interpret visual information. When we look at the circles, our brains use various visual cues, such as shading and relative size, to interpret their shape and depth. As a result, our brains interpret the concave circle as having a greater depth than the convex circle.

It has been theorized that the light on top is consistent with the sun lighting objects from above, as such, our visual system perceives the shapes on circles on the left to be solid and therefore appear convex.

The concave-convex circle illusion is a great example of how our brains can be tricked by visual information, and it highlights the complex interplay between perception, cognition, and interpretation of visual stimuli.

Some Similar Illusions

There are many similar illusions that take advantage of the way our brains interpret visual information. Here are a few examples:

  1. The Penrose triangle: Also known as the “impossible triangle,” this illusion depicts a triangle that appears to be three-dimensional, but is actually impossible to create in real life.
  2. The Ames room: This illusion uses distorted geometry to make objects appear larger or smaller than they really are, and can create the illusion of people changing size as they move around the room.
  3. The Moiré pattern: This illusion occurs when two or more grids or patterns are overlaid on each other, creating a rippling or pulsing effect.
  4. The Shepard tone: This auditory illusion creates the impression of an infinitely rising or falling sound, even though the pitch is actually staying the same.
  5. The Necker cube: This illusion depicts a cube that appears to flip back and forth between two different orientations, even though it is actually stationary.

These illusions, and many others, demonstrate the remarkable ways in which our brains interpret and process visual and auditory information, and highlight the complexity of perception and cognition.

Discovery of the Concave or Convex Illusion

The concave-convex illusion origin is not entirely clear. It is likely that the illusion has been observed and studied by many people throughout history, as similar illusions have been documented in artwork dating back to the Renaissance period.

One of the most famous examples of the concave-convex illusion can be found in a drawing by the artist M.C. Escher, who is known for his intricate and mind-bending works of art. Escher’s drawing, titled “Convex and Concave,” features a series of interlocking figures that appear to shift in and out of concave and convex shapes.

While it is not clear who first discovered or documented the concave-convex illusion, it has been studied and analyzed by scientists and psychologists for many years. In recent decades, researchers have used advanced imaging techniques and brain imaging technologies to better understand how the brain processes visual information and creates illusions like the concave-convex circle illusion.


References and Resources

In addition to the Concave or Convex Illusion check out our complete list of illusions.

Optical Art Illusions

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Optical Art Illusion

Op Art, short for Optical Art, is a style of art that emerged in the 1960s and is characterized by the use of optical illusions, geometric shapes, and bright colors to create the impression of movement, depth, and visual vibration.

If you are interested in learning more about Optical Art Illusions and seeing some more examples, scroll down to read more about it.

Optical Art Illusion
Victor Vasarely “Zebra”


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What are Optical Art Illusions?

Optical Art, short for Optical Art, is a style of art that emerged in the 1960s and is characterized by the use of optical illusions, geometric shapes, and bright colors to create the impression of movement, depth, and visual vibration.

Optical Art often employs simple geometric shapes such as squares, circles, and lines, arranged in patterns or sequences that create a sense of movement or distortion. The art form relies on the viewer’s perception and the way that the human brain processes visual information, often resulting in images that appear to be pulsing, vibrating, or even moving.

Optical Art is heavily influenced by the scientific and technological developments of the time, such as advances in color television, photography, and printing techniques, which allowed artists to experiment with new forms of optical illusions and visual effects.

The style was popularized by artists such as Bridget Riley, Victor Vasarely, and Yaacov Agam, among others, and has had a significant influence on contemporary art, design, and popular culture. Today, Op Art continues to be a popular style among artists who are interested in exploring the intersection of art and perception.

How do Optical Art Illusions Work?

Optical Art works by exploiting the way the human brain processes visual information. The style relies on optical illusions, such as the Moiré effect, in which the viewer perceives patterns or lines that are not actually present, or the illusion of movement, in which a static image appears to be in motion.

Optical Art often employs simple geometric shapes such as squares, circles, or lines, arranged in patterns or sequences that create a sense of movement or distortion. These patterns and sequences are designed to activate the viewer’s visual cortex, which is responsible for processing visual information and making sense of what we see.

When we view an Optical Art piece, our brain tries to interpret the patterns and shapes it is seeing, leading to various perceptual effects such as the impression of movement, depth, and visual vibration. These effects are created by the contrast between the different colors or shades used in the artwork, as well as the way the shapes and patterns are arranged.

Op Art works because our visual system is constantly trying to make sense of the information it receives, and the style exploits the way our brains process visual information to create images that are visually engaging and dynamic.

Some Examples of Optical Art Illusions

Optical Art is a style of art that emerged in the 1960s, characterized by the use of geometric shapes, bright colors, and optical illusions to create the impression of movement and depth. Here are some examples of Op Art:

Bridget Riley’s “Movement in Squares”: This painting, created in 1961, features a series of black and white squares arranged in a grid that creates the impression of movement and depth.

Optical Art Illusion
Bridget Riley’s “Movement in Squares”

Victor Vasarely’s “Zebra”: This painting, created in 1937, features a series of black and white stripes arranged in a way that creates a sense of vibration and optical illusion.

Optical Art Illusion
Victor Vasarely “Zebra”

Jesus Rafael Soto’s “Penetrable”: This sculpture, created in 1967, features a series of hanging wires that create an immersive, three-dimensional environment in which viewers can move and interact.

Jesus Rafael Soto’s “Penetrable”

Yaacov Agam’s “Double Metamorphosis II”: This sculpture, created in 1964, features a series of rotating panels that create a sense of movement and change depending on the viewer’s perspective.

Optical Art
Yaacov Agam’s “Double Metamorphosis III”:

These are just a few examples of Op Art, which continues to be a popular style among artists and designers who are interested in exploring the intersection of art and perception.

Discovery of Optical Art Illusions

The Optical Art movement emerged in the mid-1960s, and it is difficult to attribute its creation to a single artist or individual. The style was influenced by a variety of artistic and scientific movements of the time, including Abstract Expressionism, Kinetic Art, and the study of color and perception.

Some of the earliest and most influential Op Art artists include Victor Vasarely, Bridget Riley, and Jesús Rafael Soto. Vasarely, who is often credited with coining the term “Op Art,” began creating geometric abstract art in the 1930s and is considered one of the pioneers of the style. Riley, who emerged in the 1960s, is known for her black-and-white paintings that create optical illusions of movement and depth. Soto, who was also active in the 1960s, created sculptures and installations that engage the viewer in an immersive, three-dimensional environment.

Overall, Optical Art was a movement that emerged out of a broader cultural and artistic context, and many artists contributed to its development and popularity in the 1960s and beyond.


References and Resources

Check out our complete list of illusions.

Dynamic Luminance-Gradient Effect

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Dynamic Luminance-Gradient Effect

This illusion is an example of the Dynamic Luminance-Gradient Effect.

To make this work, you’ll need to stare at the white spot in the center and then move your face closer to the screen. When you move forward, the white spot will expand and increase in luminescence.

If you are interested in learning more about the Dynamic Luminance-Gradient Effect, scroll down to read more about it.

Dynamic Luminance-Gradient Effect


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What is the Dynamic Luminance-Gradient Effect?

The Dynamic Luminance-Gradient Effect is a perceptual phenomenon in which a static image appears to have motion or movement due to the manipulation of luminance gradients within the image. This effect is achieved by creating a pattern of luminance gradients that are organized in a specific way to produce the illusion of motion.

For example, an image of parallel lines with alternating light and dark stripes can create the impression of movement when the lines are tilted or moved in a particular direction. This effect is thought to be caused by the visual system’s sensitivity to changes in luminance contrast, which is a property of how the brightness of different parts of an image compare to each other.

The Dynamic Luminance-Gradient Effect has been studied extensively in the fields of psychology and neuroscience, as it can provide insights into how the brain processes visual information and creates the perception of motion. It is also commonly used in art and design to create visual interest and the illusion of movement in static images

How does the Dynamic Luminance-Gradient Effect Work?

The Dynamic Luminance-Gradient Effect works by taking advantage of the human visual system’s sensitivity to changes in luminance contrast. Our visual system is highly attuned to differences in brightness, and it uses these differences to identify and track objects in our environment.

When we look at an image that contains luminance gradients organized in a specific way, our visual system interprets these gradients as indicating motion. This is because our brains are wired to assume that changes in brightness over time are caused by objects moving in space.

The specific mechanisms by which the visual system processes luminance gradients and creates the illusion of motion are still not fully understood, and researchers continue to study this phenomenon to gain insights into how the brain processes visual information. However, it is clear that the Dynamic Luminance-Gradient Effect is a powerful tool for creating visual interest and the impression of movement in static images.

Some Similar Illusions

There are several similar illusions to the Dynamic Luminance-Gradient Effect that also rely on the visual system’s sensitivity to contrast and motion. Here are a few examples:

  1. Motion Aftereffect (MAE): This is an illusion in which a stationary object appears to be moving after the viewer has been exposed to a moving object for an extended period of time. This effect is thought to be caused by neurons in the visual system adapting to the constant motion, which leads to a temporary imbalance in the perception of motion.
  2. Op Art: Op art, short for optical art, is a style of art that creates the illusion of movement or three-dimensionality through the use of patterns and contrast. This style often features repeating geometric shapes or lines that are arranged in a way that creates a visual vibration or pulsation.
  3. The Pinna-Brelstaff illusion: This is an illusion in which a static image appears to rotate when the viewer moves towards or away from it. This effect is achieved by combining opposing diagonal patterns that create an impression of motion in the direction of the viewer’s movement.
  4. The Hermann Grid illusion: This is an illusion in which grey dots appear at the intersections of a grid of black lines on a white background. This effect is caused by the way that the visual system processes contrast, and it can be enhanced by increasing the size of the grid or by adjusting the brightness of the dots and background.

Discovery of the Dynamic Luminance-Gradient Effect

The Dynamic Luminance-Gradient Effect has been studied by many researchers in the fields of psychology, neuroscience, and visual perception, and it is not attributed to any one specific individual as its discoverer.

However, the phenomenon has been documented in scientific literature since the early 20th century. For example, the artist and researcher Josef Albers described the effect in his book “Interaction of Color” in 1963, and it has since been studied extensively in the context of visual perception and neuroscience.

Overall, the Dynamic Luminance-Gradient Effect is a well-established perceptual phenomenon that has been observed and studied by many researchers over the year


References and Resources

Check out our complete list of illusions.

Illusory Sunrise and Sunset

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Illusory Sunrise and Sunset

An Illusory Sunrise and Sunset creates an awe inspiring view

An illusory sunrise or sunset, also known as a “false sunrise” or “false sunset,” is a phenomenon that can occur when the sun is still below the horizon but its rays are refracted or bent by the Earth’s atmosphere. This causes the sun’s light to be visible above the horizon, creating the appearance of a sunrise or sunset.

Check out these beautiful views of Illusory Sunrise and Sunsets, and if you are interested in learning more about Illusory Sunrises and Sunsets, scroll down to read more about them.

Illusory Sunrise and Sunset
Illusory Sunrise and Sunset
Illusory Sunrise and Sunset
Illusory Sunrise and Sunset


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What are Illusory Sunrises and Sunsets?

An illusory sunrise or sunset, also known as a “false sunrise” or “false sunset,” is a phenomenon that can occur when the sun is still below the horizon but its rays are refracted or bent by the Earth’s atmosphere. This causes the sun’s light to be visible above the horizon, creating the appearance of a sunrise or sunset.

The most common type of illusory sunrise or sunset is called a “green flash,” which is a brief burst of green light that can be seen just as the sun appears or disappears below the horizon. This occurs when the atmosphere refracts the sun’s light, separating it into different colors and causing the green light to be visible for a split second.

Illusory sunrises and sunsets are most commonly seen near the ocean, where the horizon is unobstructed, and when the atmosphere is clear and stable. They are rare and can be difficult to observe, but they are considered a beautiful and fascinating natural phenomenon.

How do Illusory Sunrises and Sunsets Work?

Illusory sunrises and sunsets, also known as false sunsets and false sunrises, occur when the sun’s light is refracted or bent by the Earth’s atmosphere. The atmosphere is composed of different layers of air with varying densities and temperatures, and these layers can cause the sun’s rays to bend and scatter in different directions.

When the sun is near the horizon, its light passes through a larger portion of the atmosphere, and this causes more bending of the light. The bending is called refraction, and it causes the light to be spread out into different colors, similar to how light is separated into a rainbow by a prism. This refraction of light can cause the sun to appear to be higher or lower than it actually is, and can even create the appearance of multiple suns or a distorted sun shape.

The most common type of illusory sunrise or sunset is called a green flash. This occurs when the atmosphere separates the sun’s light into different colors, and the green light becomes visible for a brief moment just as the sun disappears below the horizon.

Overall, illusory sunrises and sunsets are a result of the bending and scattering of light by the Earth’s atmosphere, and they are a fascinating and beautiful natural phenomenon.

Some Similar Illusions

There are several other illusions that involve the bending or refraction of light, which are similar to illusory sunrises and sunsets. Here are a few examples:

  1. Fata Morgana: This is a complex form of mirage, caused by the refraction of light through different layers of the atmosphere. It can create the illusion of castles, ships, or even entire cities floating in the sky.
  2. Mirage: A mirage is an optical illusion caused by the bending of light as it passes through air layers with different temperatures. It can make objects appear to be displaced or distorted.
  3. Rainbow: A rainbow is an optical phenomenon that is caused by the refraction, reflection, and dispersion of light in water droplets. It creates a colorful arc in the sky, often seen after a rainstorm.
  4. Twilight: Twilight is the period of time before sunrise or after sunset when the sky is illuminated by indirect sunlight that is scattered in the upper atmosphere. It can create colorful and dramatic skies, similar to those seen during a sunrise or sunset.
  5. Halo: A halo is a ring of light that surrounds the sun or moon, caused by the refraction of light through ice crystals in the atmosphere. It can create a striking and ethereal visual effect.

These optical illusions are all caused by the bending or refraction of light, and they can create stunning and sometimes surreal visual experiences.

Discovery of the Illusory Sunrises and Sunsets

The phenomenon of illusory sunrises and sunsets has been observed for centuries, and the underlying science of atmospheric refraction and bending of light has been studied and explained by many scientists over the years.

One of the earliest documented explanations of atmospheric refraction was provided by the ancient Greek philosopher Aristotle, who observed that the apparent position of stars near the horizon was slightly higher than their true position, and he hypothesized that this was due to the bending of light in the Earth’s atmosphere.

In the modern era, several scientists have made significant contributions to our understanding of atmospheric refraction and the formation of illusory sunrises and sunsets. One of the most notable figures is French astronomer Pierre Bouguer, who in the early 18th century conducted experiments and wrote extensively about atmospheric refraction and its effects on celestial observations.

Another important figure in the study of atmospheric optics is English scientist Thomas Young, who in the early 19th century proposed a wave theory of light that helped to explain many optical phenomena, including the bending of light in the atmosphere.

Today, the science of atmospheric optics is a well-established field of study, and scientists continue to investigate and refine our understanding of the complex ways in which light interacts with the Earth’s atmosphere.


References and Resources

Check out our complete list of illusions.

Chromatic Adaptation Illusion

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chromatic adaptation illusion

This Chromatic Adaptation Illusion allows you to see a black and white image in full color. How?

Stare intently at the brightly colored GIF. If you continue to stare hard, you’ll be able to see the following Black & white image in full color.

If you are interested in learning more about the Chromatic Adaptation Illusion and how it works, scroll down to read more about it.

chromatic adaptation illusion
Stare intently at the brightly colored GIF. If you continue to stare hard, you’ll be able to see the following Black & white image in full color.


Table of Contents

What is the Chromatic Adaptation Illusion?

Chromatic adaptation illusion refers to the phenomenon where the colors of an object appear to change when they are viewed under different lighting conditions. This illusion occurs because the human visual system adjusts its sensitivity to different colors based on the ambient lighting.

For example, if you look at a white piece of paper under bright sunlight, it will appear to be white. However, if you look at the same piece of paper under a dimmer light, such as candlelight, it may appear to have a yellowish tint. This is because the lighting conditions have changed, and your visual system has adapted to the new lighting by adjusting the sensitivity of your color receptors.

The chromatic adaptation illusion can also be demonstrated using color patches. If you view a colored patch under one type of lighting and then view it under another type of lighting, the patch will appear to change color. This illusion is particularly pronounced with colors that are close to the edge of the visible spectrum, such as blue and violet.

Overall, the chromatic adaptation illusion demonstrates the remarkable ability of the human visual system to adjust to changes in the environment, and highlights the importance of considering the effects of lighting conditions when interpreting color perception.

How does the Chromatic Adaptation Illusion Work?

The chromatic adaptation illusion occurs because our visual system is constantly adapting to changes in the ambient lighting. When we view an object, the light that reflects off of it enters our eyes and is processed by special cells called photoreceptors in the retina. These photoreceptors are responsible for detecting color and transmitting that information to the brain.

However, the sensitivity of these photoreceptors can vary depending on the lighting conditions. For example, in bright sunlight, the photoreceptors are more sensitive to blue light, while in dim lighting, they are more sensitive to red light. This is because the photoreceptors adjust their sensitivity to different wavelengths of light based on the overall color of the light that is present.

When we view an object under different lighting conditions, our visual system adjusts the sensitivity of the photoreceptors accordingly. This adjustment process is known as chromatic adaptation. The result is that the perceived color of the object changes depending on the lighting conditions.

For example, if we view a white object under a bright blue light, our visual system adapts to the blue light by reducing the sensitivity of the photoreceptors that are most sensitive to blue light. This makes the object appear white. However, if we view the same object under a dim red light, our visual system adapts to the red light by reducing the sensitivity of the photoreceptors that are most sensitive to green light. This makes the object appear reddish.

In summary, the chromatic adaptation illusion occurs because our visual system adjusts the sensitivity of the photoreceptors based on the overall color of the ambient lighting, which can cause the perceived color of an object to change depending on the lighting conditions.

Some Similar Illusions

There are many other types of illusions similar to the chromatic adaptation illusion, which involve changes in perception due to changes in the surrounding environment. Here are some examples:

  1. The brightness illusion: This illusion occurs when the same color appears brighter or dimmer depending on the surrounding colors. For example, a gray square may appear darker when surrounded by lighter shades, and lighter when surrounded by darker shades.
  2. The contrast illusion: This illusion occurs when the perceived contrast of an object is influenced by the colors or patterns around it. For example, a gray bar may appear darker against a light background and lighter against a dark background.
  3. The color assimilation illusion: This illusion occurs when a color appears to “spread” into neighboring areas of the same or similar colors. For example, a red dot surrounded by a yellow ring may appear to have a slightly orange tint due to the influence of the surrounding yellow.
  4. The size illusion: This illusion occurs when the perceived size of an object is influenced by the surrounding context. For example, a circle surrounded by smaller circles may appear larger than the same circle surrounded by larger circles.
  5. The motion aftereffect illusion: This illusion occurs when a stationary object appears to move in the opposite direction after viewing a moving object. For example, after watching a spinning spiral, a stationary object may appear to spin in the opposite direction.

These illusions, like the chromatic adaptation illusion, demonstrate the complex ways in which our perception of the world is influenced by our surrounding environment and the workings of the visual system.

Discovery of the Chromatic Adaptation Illusion

The chromatic adaptation illusion is a well-known phenomenon in the field of color perception, and its discovery cannot be attributed to a single individual or moment in history. Rather, it has been studied and documented by many researchers over the years.

One of the earliest descriptions of chromatic adaptation was provided by the German physiologist Ewald Hering in the late 19th century. Hering proposed that the visual system adapts to different colors by adjusting the sensitivity of the three types of color receptors in the retina. This idea has since been supported by many studies in vision science.

Another important figure in the study of chromatic adaptation was the American psychologist Edwin H. Land, who is best known for his invention of instant photography. Land conducted numerous experiments on color vision and chromatic adaptation in the mid-20th century, and his work helped to establish the principles of color constancy and color adaptation that are still used today.

Since then, many researchers in vision science and related fields have contributed to our understanding of the chromatic adaptation illusion, including David Brainard, Michael Webster, and Andrew Stockman, among many others. The study of color perception remains an active area of research, and new insights into the workings of the visual system continue to be discovered.


References and Resources

Check out our complete list of illusions.

Color Afterimage Illusions

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Color Afterimage Illusion

These Color Afterimage illusions occur when an image continues to appear in our visual field after we stop looking at it.

To give these color afterimage illusions a try, stare at each of the designs for 30 seconds and then stare at white surface. You’ll end up seeing the “opposite” or “complimentary” colors.

If you are interested in learning more about Color Afterimage Illusions, scroll down to read more about them it.

Color Afterimage Illusion
Stare at this for 30 seconds and then look at a white surface. You should see the familiar red, white, and blue because they complementary colors of cyan, black, and yellow.
Color Afterimage Illusion
Stare at this for 30 seconds and then look at a white surface. You should see the familiar green, white, and red of the Italian Flag.
Color Afterimage Illusion
Stare at the white dot for 30 seconds and then close your eyes. You should see a cyan circle
Color Afterimage Illusion
Color Afterimage Illusion
Stare at the center of a single circle for 30 seconds then divert to a white surface. Experiment with the different colors.


Table of Contents

What are Color Afterimage Illusions?

Color afterimages are a type of afterimage that occurs when we look at a colored object or image for a prolonged period of time, and then look away to a neutral background. The afterimage that we see appears in the complementary color to the original color of the object or image.

For example, if we stare at a red object for a period of time, the afterimage that we see when we look away will appear in green, which is the complementary color of red. Similarly, if we stare at a green object, the afterimage that we see will appear in red. This phenomenon is known as “negative afterimage” or “complementary afterimage”.

The reason for this phenomenon is that the photoreceptor cells in our eyes that detect color are most sensitive to certain wavelengths of light. When we stare at a colored object for a period of time, these photoreceptor cells become fatigued, and their sensitivity to the color in question decreases. When we then look away to a neutral background, the photoreceptor cells that were not fatigued are still sensitive, and they respond strongly to the complementary color, creating the illusion of a color afterimage.

Color afterimages can be a fascinating and beautiful visual experience, and they have been used in art and design to create interesting and striking visual effects. However, they can also be a useful tool for researchers studying visual perception and the mechanisms of color vision.

How do Color Afterimage Illusions Work?

Color afterimages are a type of optical illusion that occurs when you look at a brightly colored object for a period of time and then look away, only to see a ghostly image of the object in a different color. These afterimages are created by the way that our eyes and brain process color information.

When we look at a brightly colored object, the light from that object stimulates specialized cells in our eyes called cone cells. These cone cells are responsible for detecting different colors, and they send signals to our brain that help us perceive the color of the object.

However, when we look at a brightly colored object for a period of time, these cone cells can become fatigued or “adapted” to the color of the object. This means that they become less sensitive to that color over time, and when we look away from the object, they continue to send signals to our brain that create the perception of the opposite or complementary color.

For example, if you stare at a red object for a period of time and then look away, you may see a ghostly image of the object in green. This is because green is the complementary color to red, and when the cone cells that are responsible for detecting red become fatigued, they send signals to the brain that create the perception of green.

Overall, color afterimages are a fascinating example of how our eyes and brain process color information, and they can be used to study the mechanisms of perception and cognition.

Some Similar Illusions

There are several types of illusions that are similar to color afterimage illusions, as they involve the way our eyes and brain process visual information. Some examples include:

  1. Motion aftereffect illusion: This illusion occurs when we view a moving object for a prolonged period of time, and then look at a stationary object. The stationary object appears to be moving in the opposite direction to the original moving object.
  2. Contrast illusion: This illusion occurs when we view a dark object against a light background, and then view a light object against a dark background. The light object appears brighter and more intense than it actually is, while the dark object appears darker and less intense.
  3. Color adaptation illusion: This illusion occurs when we view a colored object for a prolonged period of time, and then look at a neutral colored object. The neutral object appears to have a tint of the complementary color to the original colored object.
  4. Troxler’s fading illusion: This illusion occurs when we stare at a fixed point on a stationary image, and the other parts of the image begin to fade away over time. This happens because our brain filters out visual information that is not changing, allowing us to focus on important visual stimuli.

Overall, these illusions demonstrate the complex and dynamic ways in which our eyes and brain process visual information, and they continue to fascinate researchers and laypeople alike.

Discovery of Color Afterimage Illusions

The phenomenon of color afterimages has been known for centuries, and it is likely that many ancient cultures observed and discussed the phenomenon. However, the scientific study of afterimages and their underlying mechanisms began in the 19th century, with the work of several researchers.

One of the first researchers to study afterimages was a German physicist named Georg Christoph Lichtenberg, who conducted experiments in the late 18th century to investigate the nature of visual afterimages. Another early researcher in this field was the French physiologist Etienne-Jules Marey, who published a series of studies on visual perception and afterimages in the late 19th century.

However, it was the German physicist Hermann von Helmholtz who made some of the most important contributions to the study of afterimages in the 19th century. Helmholtz conducted numerous experiments to investigate the mechanisms of afterimages, and his work laid the foundation for much of the modern understanding of visual perception.

Today, afterimages remain a topic of ongoing research and fascination among scientists, psychologists, and artists alike.


References and Resources Color Afterimage Illusions

In addition to Color Afterimage Illusions, please check out our complete list of illusions.

Color Assimilation Grid Illusion

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color assimilation grid illusion

In these Color Assimilation Grid Illusions, all the images are completely black and white except for some colored lines superimposed on the original image.

Our brains have the fill in the missing color based on the context of the surrounding visual stimuli.

If you are interested in reading more about the the illusion, scroll down to learn more about it.

color assimilation grid illusion
color assimilation grid illusion
color assimilation grid illusion

Table of Contents

What is the Color Assimilation Grid Illusion?

The color assimilation grid illusion, also known as the Chubb illusion, is a perceptual phenomenon where black and white grid lines appear to take on the color of the surrounding grid squares when a few colored lines are added to the image.

The illusion is created by overlaying a grid of black and white lines on a background of colored squares. The colored squares are typically of different colors, and a few colored lines are added to the grid. When the image is viewed, the black and white lines appear to take on the color of the surrounding squares, creating the illusion that the entire image is in color.

The exact mechanisms underlying the color assimilation grid illusion are still not fully understood. However, it is thought to be caused by the way in which neighboring colors and lines interact with each other, and how the brain processes and interprets visual information. The illusion is a fascinating example of how our perception of color can be influenced by surrounding visual stimuli.

How does the Color Assimilation Grid Illusion Work?

The Color Assimilation Grid Illusion, also known as the Chubb illusion, works due to the way our brains process visual information. Our brains have the ability to fill in missing information based on the context of the surrounding visual stimuli.

In the case of the Color Assimilation Grid Illusion, the black and white lines of the grid are surrounded by colored squares. When a few colored lines are added to the image, our brains try to make sense of the new information by processing it in relation to the context of the surrounding colors. As a result, the black and white lines take on the hue of the surrounding colored squares, giving the illusion that the entire image is in color.

This phenomenon is also known as color assimilation, where the colors of adjacent areas can influence the perceived color of an object or area. The exact mechanisms underlying the illusion are not fully understood, but it is believed that they involve complex interactions between the visual system’s processing of color and brightness, the integration of visual information across spatial locations, and the influence of contextual information on visual perception.

Overall, the Color Assimilation Grid Illusion is a fascinating example of how our perception of color can be influenced by surrounding visual stimuli, and how our brains work to fill in missing information based on the context of the visual environment.

Some Similar Illusions

There are several illusions that are similar to the Color Assimilation Grid Illusion in that they involve the influence of surrounding visual stimuli on our perception of color and brightness. Here are a few examples:

  1. Mach bands illusion: This illusion involves the exaggeration of contrast at the edges of a gray scale. When two adjacent gray bars of slightly different brightness are placed next to each other, the edges between them appear to be darker and lighter than they actually are, creating a banding effect.
  2. Simultaneous contrast illusion: This illusion occurs when a color is perceived differently depending on the colors that surround it. For example, if a gray patch is surrounded by a black background, it will appear lighter than if it is surrounded by a white background.
  3. White’s illusion: This illusion involves the perception of brightness and size of circles. When a small circle is surrounded by a larger circle of the same brightness, the smaller circle appears darker and smaller than it actually is.
  4. Hering illusion: This illusion involves the perception of the curvature of lines. When two parallel lines are surrounded by converging or diverging lines, they appear to be curved.
  5. Adelson’s checkerboard illusion: This illusion involves two squares of different shades of gray placed next to each other on a checkerboard pattern. Although the two squares are of different shades, they appear to be the same shade due to the influence of the surrounding squares.

These are just a few examples of the many illusions that exist and demonstrate the fascinating ways in which our perception of color and brightness can be influenced by the surrounding visual environment.

Discovery of the Color Assimilation Grid Illusion

The Color Assimilation Grid Illusion, also known as the Chubb illusion, was first described by two researchers named George Mather and David H. Kelly in a scientific paper published in 1997. They named the illusion after one of their graduate students, Michael Chubb, who had discovered it during a class demonstration.

Mather and Kelly’s paper, titled “The Measurement of Visual Motion,” reported the results of several experiments they conducted to study the perception of motion in visual stimuli. As part of these experiments, they observed the Color Assimilation Grid Illusion and recognized it as a novel and interesting visual phenomenon.

Since the initial discovery of the Color Assimilation Grid Illusion, it has become a popular topic of study for researchers in the field of visual perception, and it continues to be used as a tool for investigating the mechanisms of color perception in the human brain.


References and Resources

Check out our complete list of illusions.