When Optical Art Meets Illusion

Some simple geometric patterns and designs, when repeated, can induce strong illusory shape distortions. Thus, visual misperceptions are very common in the op art world.

If dark and clear rectangular tiles are arranged in a checkered fashion, as shown below, there is obviously no illusion, but wait, just add at the intersection of these tiles some transparent dark and clear square patches, et voilà, magic appears!

So, transparencies can produce apparent linear distortions. The parallel red lines in this example look like being convergent / divergent.

ZigZag, 2003
Available as prints and canvases from my online gallery
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Amazing Brightness Constancy Effect

Look carefully at the saw-tooth wave patterns on this picture. Is the background of the picture uniformly gray or are there different shades of gray?

Kolozanges (2013-2021), © Gianni A. Sarcone

Brightness constancy makes some vertical strips look darker, when in fact the gray background is all the same shade of gray.

This op art work is available as prints and canvases from my official online Gallery.

Turning Gray Shades Into Colors With A Tinted Geometric Grid

explanation

This is an old technique that uses the “color assimilation” effect to colorize pictures. This perceptual effect, also known by scientists as the Von Bezold spreading effect, occurs when our visual system transfers perceived colors to their adjacent areas.

Is the first photo of a variety of pumpkins in color?

colorized black and white pumpkins
Black and white photo overlaid with a geometrical tinted grid

Ghost Colors

This is one of my earliest color optical illusions. There is no yellow or green in the diamond shapes, just vertical black lines! (If you don’t believe it, use a eyedropper tool to check it.) This intriguing visual effect is mainly due to “simultaneous color contrast induction“.

Illusive colors
Ghost Squares / Black Diamonds (2002 – 2007)
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Scintillating Starburst: Seeing rays that aren’t there…

This is one of my oldest illusions I created in the 90s. In the picture you may see ghostlike dark radial beams. This illusion is a variant of the Herman’s scintillating grid illusion. I designed this illusion just by turning 45 degrees the Herman grid and then by applying a polar transformation.

From my book “Eye Tricks“, 2001-2007.
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Mondrian Meets… (My Tribute To Mondrian)

Here are two projects involving the geometrical-constructive art of Piet Mondrian, one of my preferred artists, the golden ratio and ϕ. For this purpose, I used the same color palette favored by Mondrian: yellow, red, blue, black and gray.

Mondrian meets Pythagoras and Fibonacci

In the first project, I used squares, that are proportional to each other by the golden ratio or ϕ, to prove the Pythagorean theorem as shown in the Zhoubi Suanjing (or Chou Pei Suan Ching – 周髀算經), one of the oldest Chinese mathematical texts (circa b.c. 200).

Zhoubi Suanking theorem Continue Reading