Why do afterimages occur?
There are instances in our life wherein we still continue to see images even if we stopped looking at the original picture. This occurrence is called an afterimage. This happens because of our vision. There are times when a series of lines seem to float even if they do not. This is an example of an optical illusion that our eyes seldom experience.
Afterimages occur because our vision has the capacity to portray motion. That’s why pictures in rapid motion seem to portray action. The main reason why afterimages happen is because of the sensory signals brought to the brain. The visual system of a human can interpret the colors we see. The more we look at a picture, the more chances that color patches will be registered in our brain thus creating an afterimage if we look at a blank, white page.
Afterimages can be best experienced with colors. For negative afterimages, a white screen can appear to be colored because there are special colors filtered by the eyes. So when we lift our eyes from the color and look at a white page, it appears that another color is seen. It is called a negative afterimage because the colors differ upon looking at another page. Red becomes cyan, black becomes white, and green becomes magenta.
Positive afterimages may occur because of the persistence property or what can stay in the brain at a certain time. Another reason is the latency property. This explains why visual stimulation signals don’t immediately reach the brain. The amount of light that strikes the eye can also be the reason why afterimages occur. The more light there is, the faster the brain will process what we see.
With the properties of latency and persistence working together plus the high frequency of light, optical illusions may occur which cause afterimages.
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