Studying anything mildly related to the field of visual perception was of great interest to him. During his research, he came upon the Checker Shadow illusion, and after carrying on an in-depth study of his own on the unusual finding, he published it for readers, scientists, professors, and his students so they too, could gain exposure to this optical illusion.
The Illusionary Effect of the Checker Shadow Illusion
When he published the optical illusion, it appeared to be a checkerboard thus the name. In the picture, you will see that it is made up of both dark and light color squares. One square will appear darker in color than the other. Even though the two boxes appear to be a different color from each other, they are, in fact, the same shade. If you do not believe it, open it up in an image editing software.
The Proof of the Two Colors Being the Same
Copy the Checker Shadow illusion and paste it in an image editing software. Next, use the eyedropper tool to confirm that the two colors are the same. If you are upset over being proven wrong, take your frustration out on the illusion.
You can take the effect of the optical illusion away by viewing patches of the black and white squares without the context surrounding it. You can even separate the squares from each other to eliminate the Checker Shadow illusion. Now, that you know that the colors are the same, you should know the working behind the optical illusion.
The Checker Shadow Illusion—the Explanation
According to Adelson, the visual system has one sole purpose—to distinguish the colors of the world. In his explanation, he writes that a cast shadow will dim an area in order to let a white area in a shadow reflect less light than a dark surface in complete brightness. In the Checker Shadow illusion, the light checkered boxes are surrounded by darker checkered boxes. Even if a checkered box is considerably darker, it is lighter when compared to its surrounding boxes and vice versa.
Your visual system is ignoring the changes in the light level in order to determine the shade of the area without having the shadows misled it to thinking otherwise. Your visual system is breaking down the picture information into parts to view the nature of the object in front of it.
The Checker Shadow illusion is one of the most sensational illusions, as it lets viewers perceive all the boxes as a different color when all of them are the same. You can feel free to dissect the optical illusion apart to see for yourself that the checkerboard is indeed one color.