Try to see that... Squares A and B are the SAME Color and Shade. No matter how hard you try... you will see them as different... BUT they are... exactly the SAME Color & Shade.
You can do this simple experiment. Download the STILL Image and use an Image Software like Paint Brush (or any other software you are familiar with) to help you See the Truth... OR... See the GIF Animation Image below.
GIF Animation Image
My Video of this Experiment
optical iLLusion ~ Squares A & B are the SAME Colour & Shade
Checker shadow illusion
From Wikipedia, the free encyclopedia
The checker shadow illusion is an optical illusion published by Edward H. Adelson, Professor of Vision Science at MIT in 1995. The image depicts a checkerboard with light and dark squares. The optical illusion is that the area of the image labeled A appears to be a darker color than the area of the image labeled B on the 2D plane of the rendered 3D projection. However, they are actually exactly the same color on the 2D plane of the image file (but not necessarily in the 3D projection) which becomes especially obvious if the projected 3D scenery is rendered partially or entirely defective.
That the two squares are of the same color on the 2D plane can be proven using the following methods:
- Opening the illusion in an image editing program and using the eyedropper tool to verify that the colors are the same.
- Cut out a cardboard mask. By viewing patches of the squares without the surrounding context, you can remove the effect of the illusion. A piece of cardboard with two circles removed will work as a mask for a computer screen or for a printed piece of paper.
- Connecting the squares with a rectangle of the same color, as seen below in the middle figure.
- Using a photometer.
- Print the image and cut out the squares. Cut out each square along the edges. Remove them. Hold them side by side.
- Isolating the squares. Without the surrounding context, the effect of the illusion is dispelled. This can be done by using the eyedropper tool in image editing programs, such as Gimp to sample the values of A & B, and to color in the newly adjacent rectangles using the paint bucket tool.
Areas of the image A and B are the same color
The original image plus two vertical stripes of the same
shade of gray to make the colour equivalence more clear
A rectangle of the same color has been drawn
connecting the two areas of the image
As an explanation as to why the illusion works, Adelson writes:===.
More explanation here...