Under the Hood

After Imaging: Staring At These Bright Colors Will Trick Your Brain

After Imaging: Staring At These Bright Colors Will Trick Your Brain
Vision is incredibly complicated, and it’s possibly why we can experience such a wide variety of mind-boggling optical illusions — like the endless debate over the color of “the dress,” or the direction of the spinning dancer. Humans have the ability to discern between 2.3 million colors, but sometimes even our eyes can trick us into seeing colors that aren’t really there.In a new video, AsapSCIENCE describes an optical illusion that occurs after we stare at bright colors on a screen or paper for a long period of time. When you stare at the green dot in the video, and the image switches to a black and white one, you’ll find that your eyes create color where there is none.“Even though you were staring at a black and white image, your brain perceived it to be in color,” the narrator states. This is a phenomenon known as “after imaging,” in which your eye’s photoreceptors (rods and cones) become used to overstimulation in staring at colors, and then lose sensitivity. As you stare at bright colors for a long period of time, your cones become fatigued and the supply of photo pigments become exhausted.The letters that were the color of cyan in the darker image, over time, begin to appear less and less cyan; and when the image changes, you’ll notice that the letters suddenly appear red even in a black and white photo. Red is cyan’s complimentary color in the RGB color model, and the perceived color switch happens because the opposite of the eyes’ fatigued blue cones — the red cones — begin over-compensating. In the darker image, cyan fades more to white because perceived red color is being added in, but when the white image appears, only the perceived red is visible.The Dresden University of Technology describes after imaging as scenarios in which “your photopigment is ‘bleached’” by constant stimulation. “The desensitization is strongest for cells viewing the brightest part of the figure, but weaker for cells viewing the darkest part of the figure. Then, when the screen becomes white, the least depleted cells respond more strongly than their neighbors, producing the brightest part of the afterimage: the glowing light bulb… Most afterimages last only a few seconds to a minute, since in the absence of strong stimulation, most nerve cells quickly readjust.”To check it out for yourself, watch the video and see how your eyes trick you. Youtube

Vision is incredibly complicated — it’s possibly why we can experience such a wide variety of mind-boggling optical illusions. Remember the endless debate over the color of “the dress" or the direction of the spinning dancer? While humans have the ability to discern between 2.3 million colors, sometimes our eyes can trick us into seeing colors that aren’t really there.

In a new video, AsapSCIENCE describes an optical illusion that occurs after we stare at bright colors on a screen or paper for a long period of time. When you stare at the green dot in the video and the image switches to a black and white one, you’ll find that your eyes create color where there is none. “Even though you were staring at a black and white image, your brain perceived it to be in color,” the narrator states.

This is a phenomenon known as after imaging, in which your eye’s photoreceptors (rods and cones) become used to overstimulation in staring at colors, and then lose sensitivity. As you stare at bright colors for a long period of time, your cones become fatigued and the supply of photo pigments become exhausted.

In a darker image, the letters that were the color of cyan began to appear less and less cyan over time; and when the image changed, the letters suddenly appeared red even in a black and white photo. Red is cyan’s complimentary color in the RGB color wheel, and the perceived color switch happens because the opposite of the eyes’ fatigued blue cones — the red cones — begin over-compensating. Cyan fades more to white in the darker image because a perceived red color is being added in, but when the white image appears, only the perceived red is visible.

The Dresden University of Technology describes after imaging as scenarios in which “your photo pigment is ‘bleached’” by constant stimulation. “… Most afterimages last only a few seconds to a minute, since in the absence of strong stimulation, most nerve cells quickly readjust.”

To check it out for yourself, watch the video and see how your eyes trick you.

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