Afterimages

Afterimages (pronunciation: /ˈæftərˌɪmɪdʒ/) are a type of optical illusion in which an image continues to appear in one's vision after the exposure to the original image has ceased. This phenomenon is a result of the visual perception and processing system in the human brain.

Etymology

The term "afterimage" is derived from the prefix "after-", meaning "following in time or order", and "image", referring to a representation of the external form of a person or thing in art.

Types of Afterimages

There are two main types of afterimages: positive afterimages and negative afterimages.

• Positive Afterimages are an afterimage in the same color as the original image. They are typically brief, lasting less than half a second.
• Negative Afterimages are an afterimage in complementary colors to the original image. They can last for a longer period of time.

Causes

Afterimages are caused by photoreceptor cells in the eyes becoming fatigued and overstimulated. When these cells are exposed to a strong light source, they can continue to send signals to the brain even after the light source is removed.

Related Terms

• Optical Illusion
• Visual Perception
• Photoreceptor Cell
• Eye
• Positive Afterimage
• Negative Afterimage

See Also

• Visual System
• Visual Cortex
• Retina

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