Gianni A. Sarcone's profile

Experimenting The Subjectivity Of Colors

"People can have the 'Model T' in any color - so long as it's black" 
- Henry Ford
"The only color I don't have is navy brown" 
- Yogi Berra

It has been known since ancient times that color is a matter of subjective sensitivity. No two people see the same colors! This is because colors are influenced by various factors such as physical, biological, and psychological factors.

Our brain is an excellent "comparative computer," but it doesn’t always get things right when it comes to color... On this page, you will discover fascinating optical illusions and effects created by colors, including color constancy, simultaneous color contrast, color adaptation, and assimilation.

Stained Glass Illusion
Take a look at the panes indicated by arrows. Are they the same color?
The pane that appears green is, in fact, the exact same color as the pane that appears red! (Refer to the animated GIF below)

This illusion was showcased in the August 2015 issue of BBC Scienza, Italy.
Illusive Color Sofa
Take a look at the sofa and answer this simple question: Which broad stripe of fabric, B or C, has the exact same shade of gray as the broad stripe A?
The picture below demonstrates that stripes A and C have the exact same shade. A color always appears brighter when surrounded by dark colors or darker when placed on a light background. This experiment illustrates that perceived brightness is not solely determined by the amount of light that reaches the eye from the observed object.
What Color Are The Pills?
Take a look at these two pills. Can you determine their color? Do they appear blue and yellow or gray and gray?
Watch the animation below, as the background is removed and the answer will be revealed.
The yellow hand and background make the gray pill appear to be blue, while the blue hand and background make the gray pill appear yellowish.
Cat’s Eyes
At first glance, it appears that this cat has green eyes. However, in reality, only one eye is green – the other one is shown in black and white but seems tinted because of the purple context. This can be observed in the animation further below...
Thanks to a mechanism of color adaptation, the brain desensitizes itself to the purple veil which covers the right side of the cat’s face and by doing that it subtracts a bit of purple from the gray eye, which then becomes yellowish-green. As shown in the animation below.
This illustration has been taken from my book "Super Optical Illusions"
There is also a French version of the book here.
Bovine Fly
This illusion shows the interaction between color perception and afterimages. As you can see, the left image representing a cow has a color imbalance: there is too much blue on one side and too much yellow on the other.
Now fixate your gaze on the fly in the right color table for 30 seconds: this staring will make your eye adapt to a blue hue on the left and yellow on the right. As a result, your left visual field will become less sensitive to blue and your right visual field less sensitive to yellow. Then, when you look back at the fly on the cow’s nose, the image will appear to have a perfect color balance!
This illustration has been featured in the Scientific American magazine.
Colorize The Tiger
To "magically" restore the colors of the photo of the tiger stare at the small cross in the middle of the blue pattern for about 15 seconds. Then quickly look again at the tiger!
This illustration was taken from my book “Eye Bogglers”.
Enjoy also this animated version of the above experiment!
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Thank you for visiting!

Gianni A. Sarcone
Author, Artist and Researcher in Visual Perception
Experimenting The Subjectivity Of Colors

Experimenting The Subjectivity Of Colors

Visual experiments involving colors and shades