When you use this hands-on exhibit…you’ll look at a picture of chess pieces which are pictured against black or white ‘fog’.
The chess pieces appear to be different shades of grey, but when you slide a plain grey panel over the chess pieces, they change shade before your eyes.
This chess piece illusion (originally developed by Professor Bart Anderson) reveals how your brain processes three layers of information when you’re trying to work out how light or dark something may be.
If your brain didn’t compare contrasts and boundaries between objects, you wouldn’t be able to read a book in dim light or see things under moonlight.
Your visual system uses a series of filters to know that shadows are just shadows.
Every time you look at an object, your brain assesses the illumination, reflectance and transparency of something to determine how light or dark it is.
The rows of chess pieces in this Perception Deception exhibit are the same, but they’re placed against black fog or white fog surroundings.
Because your brain compares the chess pieces to their foggy surroundings, you mistakenly (but understandingly) assume that the rows of chess pieces must be darker or lighter than each other.
The foggy surroundings make the chess pieces appear darker or lighter, because your visual system breaks the pictures down into three layers:
Somehow, your brain makes allowances for these different contexts and adjusts for the conditions.