Negative Afterimage
and Other Visual Experiments

Negative Afterimage Review

Who knows what form the forward momentum of life will take
in the time ahead or what use it will make of our anguished searching?
The most that any one of us can seem to do is to fashion something --
an object or ourselves -- and drop it into the confusion,
make an offering of it, so to speak, to the life force.

--Ernest Becker, The Denial of Death

In order to see the larger picture, let's first turn our attention to science and the evolutionary study of the eye.

Among the first scientists considering the anatomy and physiology of the human eye was Pythagoras in the 6th Century BC. He believed objects were seen by rays emerging from the eye striking the objects.

Two thousand years ago, the Greek philosopher Democritus proposed that matter consists of atoms and believed that objects gave off atoms that struck the eye and caused it to see.

Another Greek philosopher, Empedocles, believed that an invisible substance radiating from the eyes caused sight. Euclid also believed the eyes projected a series of individual rays.

Aristotle discarded the idea of rays radiating from the eye and taught that the lens itself did not exist during life but was only a coagulation formed after death.

Plato, a generation later, believed that rays from the eye mingled with light rays emitted by objects and caused the eye to see.

Ya' qub ibn-Ishaq al-Kindi, an Arab philosopher, defended Euclid's ray theory and attempted to prove it by eliminating those of Plato, Aristotle, and Democritus. Al-Kindi did not agree with Euclid entirely, proposing that rays flowed in one continuous stream.

Greek physician Galen revived the Pythagorean belief, but believed the optic nerves were channels carrying visual essences from the brain which irritated the air outside the eye. Then the excited air reached the objects, causing the eye to see them.

Avincenna, an Islamic philosopher, defended Aristotle's ideas that rays from the eyes could not possibly reach the stars and rejected Galen's theory.

Second Century BC eye operations in the Egyptian city of Alexandria gradually advanced knowledge of the human eye. The muscles, iris, lens, and retina were discovered during operations.

Then 11th Century Islamic scholoar Alhazen attacked the ray theory, demonstrating that light affected the eye and anyone staring at the sun felt pain. He integrated anatomical, mathematical, and physical ideas, theorizing the eye worked like a primitive camera. Alhazen believed that "light" shone through the pupil, through a lens, and produced an image on the retina. His was the first idea that "light" created sight.

Eyeglasses were in use by the early 14th Century, although no one knew how or why they helped vision. People merely looked through various eyeglasses until a pair was found that improved vision. 17th Century German astronomer Johannes Kepler discovered the eyeglass lenses and the eye's lens correct vision by bending light rays. The degree of bend depends on the lens shape and thickness.

Then Isaac Newton theorized that light consisted of vibrating particles of varied sizes flowing in straight rays from illuminated objects. He believed that the prism divided light resulting in bands of different colors.

The next major advance in understanding the eye came in 1851, when German scientist Hermann von Helmholtz invented the ophthalmoscope, the eye-examination tool used today. Theories then surfaced that chemicals in the retina were sensitive to red, green, and violet, and that color vision depended upon these substances.

In 1877, Wilhelm Kuhne discovered that the retina contained light-absorbing chemicals called rhodopsin. Kuhne's experiments with rabbit retinas showed that light entering the eye changed the rhodopsin, and that light-changed rhodopsin formed images.

Sir Isaac Newton had claimed light was made of tiny "particles" discharged by the sun or other shining objects. But this claim was disputed by Christiaan Huygens, who proposed light consisted not of solid particles but of energy "waves."

Finally, Albert Einstein, a 20th Century scientist, led others to understand not only the function of the eye but the mysterious nature of light itself with its opposite forms. Einstein's theory of matter and energy were that they are different forms of the same thing, as steam and ice are different forms of water. Therefore, light behaves somewhat like matter, as in the particle theory, and somewhat like waves, as in the energy theory. This led to a clearer understanding of how light is received by the human eye.

Negative afterimage information and descriptions:

  • Seeing With The Mind's Eye by Mike and Nancy Samuels.
    "Another common type of visual experience is the after-image. This image typically takes place after looking at a bright object against a dark background, such as a bolt of lightning seen at night. If a person closes his eyes right after the flash, he will continue to see a light flash against a dark background. The original image lasts only a few seconds. It is followed by a negative after-image. If the original image is seen in black and white, the tones of the after-image are reversed. If the original image is in color, the negative after-image is seen in the complimentary colors. After-images cannot be scanned, that is, the image shifts as a person moves his eyes. Most people are not aware of after-images until they are told of their existence. Then, with practice, they are able to see them. People who spend prolonged periods staring at the same scene, for instance looking through a microscope, often experience a recurrent image. This image may occur immediately after looking at the original scene, or several hours later when they close their eyes to rest. People usually have little control over the appearance and disappearance of these images" (Samuels, Seeing With the Mind's Eye, P. 55).

  • Information describing afterimages was found under the name of Tattvic tides (Butler, The Magician, P. 84).
    W.E. Butler explained "complementary colors as being tuned into psychic energy in both ourselves and in the objective planes" (P. 84). He described using an object with light and dark contrasts, throwing the eyes out of focus to bring the visual picture mentally within the head. He calls it a "psychological "trick" to bring the visual image into mental apprehension." Butler suggested a further exercise is "to close the eyes -- during the first attempts only slightly, then more fully in subsequent ones, until the final stage is reached when the student is able to see clearly inside his head, as it were, the picture of the object concerned, his eyes being closed in the meantime" (P. 66). The the student "should now open his eyes sufficiently to see the disc or mirror (which should be in dim light) whilst still holding the picture on the mental screen. Then by a quiet effort of will he should project the picture outwardly onto the screen" (Butler, P. 67).

  • 1993 and 2004 New Encyclopedia Britannica's afterimage description remains unchanged and states:
    "AFTERIMAGE, a visual illusion in which retinal impressions persist after the removal of a stimulus, believed to be caused by the continued activation of the visual system. The afterimage may be positive, corresponding in colour of brightness to the original image; or negative, being less bright or of colours complementary to the original. A common afterimage is the spot of light one sees after a flashbulb has been fired. The afterimage is the most readity observed of the class of phenomena known as aftersensations, or aftereffects" (Encyclopedia Brittannia, P. 137).

  • New World New Mind by Robert Ornstein:
    "A classic demonstration of afterimages, too, can be very instructive. Students can be told to stare a a red square against a white background for a minute. If they then take the square away and look at the background, they will see an afterimage of its complementary color, green. Staring a a black square produces white. Blue produces a yellow afterimage. The color of these afterimages results from the way the ganglion cells of the retina code color information. The afterimages are not, obviously, present in the world: they are a product of our mind. What is important about this is not the colors themselves, but the fundamental understanding: There is no color in nature, no sound, but what we experience is in truth like the afterimage -- a product of the nervous system picking and choosing to construct its caricature of the world" (Orstein, New World New Mind, p. 207).

  • The eleventh century scholar Alhazen who was in agreement with the visual ray theory, showed by staring at the sun that light affected the eye. He felt pain and explained how color affected the eye by shifting one's gaze from a brightly colored object, creating a colored afterimage or a lingering impression. He concluded objects illuminated by light send out rays of light and color in straight lines to the eyes (Wertenbaker, The Human Body, P. 14-15).

  • Observing the sun's negative afterimage in yellow or blue for up to an hour after sungazing is also mentioned on the Sun Gazing Web Site under Sun Gazing Methods Most Commonly Used. See Sungazing.

  • Additional afterimage information surfaced in the book The Mind--Into the Inner World, P. 63:
    "The compensatory processes operating to permit such constancy in perceived size can be readily observed if you produce an afterimage by staring for a few seconds at a bright light or a black spot on a white page, then look first at a near surface, then at surfaces farther away. As you view the more distant surfaces, the afterimage appears to increase in size. The brain is compensating for the reduction in the size of the retinal image which usually occurs when an object is viewed from an increasing distance".

  • Peter K. Kaiser's links to Funthings and Afterimages. Joy of Visual Perception.

  • Afterimages under Exploratorium Snacks discusses "desensitized retina," "negative afterimages on the retina," "afterimage size is unchanging, only one's interpretation of the size changes." Snacks Afterimage.

  • Read about "tired" or "fatigued receptors" causing negative afterimages. Tired Receptors.

  • Scan the filling in afterimage demo web site. Filling in Afterimage Demo.

  • Consider more information on rods, cones, plus holography. Rods, Cones, Holography.

  • Review afterimages as abnormal sensory experiences. Abnormal.

  • Analyze a copycat article on fatigued receptors. Fatigued Receptors.

  • Check out attention with negative afterimages. Attention with Negative Afterimages.

  • Imagine another explanation for afterimage cell fatigue. Cell Fatigue Variation.

  • Search afterimages and contrast effects. Afterimages and Contrast Effects.

  • Next: Afterimages

© Copyright Mary Coffin Johnston

Contact info:
Mary Coffin Johnston