The human eye has evolved over millions of years.
However, the eye never shows us reality: it only gives us our “interpretation” of the light rays that are reflected. Our brain sorts and filters this information and sometimes lets things get in the way or adds additional information that is not actually present.
These “misinterpretations” are very clearly illustrated by optical illusions.
None of these images is animated. Focus on one point and the movement stops.
Colour blindness refers to an inability to see certain colours. People who are colour-blind have a more difficult time distinguishing the colours red or green. Those who cannot see green are more common than those who cannot see red. Significantly more men are affected by this.
Can you see the numbers?
The most common form of metamerism is illuminant metamerism. This describes when two colours match under some illuminants but not others.
Here, metamerism is caused by the different light spectrums of the illuminant in question.