Stare at a Red, See a Green Dot

Hello All:

I'm sure you've tried the fun experiment of staring at a red dot or a red star for 30 seconds and then looking at a white sheet of paper which results in a green dot or green star (depending on the shape you used).

Why does this happen?

Stare at a Red, See a Green Dot

The phenomenon is called an afterimage. It is caused by the way your eyes perceive color. When you look at a red dot for 30 seconds, the cells in your eyes that are responsible for seeing red become fatigued. When you then look away, you will see a green dot because the cells that are responsible for seeing green are not fatigued and are able to see the green dot. This effect is temporary and will go away after a few minutes.

So does this mean that red and green opposites? You might conclude this if you stare at different colored dots. You already stared at red dot which resulted in a green dot. But try staring at an orange dot, it will result in seeing a blue dot. Stare at yellow dot, and it will result in a violet dot. The reverse happens with green, blue and violet.

Red and green, however, are not opposites. They are complementary colors, which means they are located opposite each other on the color wheel. Complementary colors are said to be opposites because they cancel each other out when mixed together. For example, when you mix red and green paint, you get brown.

Just like the initial experiment of staring at a red dot to see a green dot, color afterimages are due to the cells in your eyes that are responsible for seeing that color become fatigued. The eye has three types of cones, which are the cells that detect color. These cones are most sensitive to red, green, and blue light. When you stare at a color for a long period of time, the cones that are sensitive to that color become fatigued. This means that they are less able to detect that color. When you then look away, the cones that are not fatigued are able to detect the complementary color. Again, the effect is temporary and will go away after a few minutes. 

***

This article was developed with the help of Bard, a large language model from Google AI. Bard is always happy to help people create content, and is always looking for ways to improve. If you wish to put Bard to work for you please visit: https://bard.google.com/