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

Paradoxical Elastic Squares

A math-magic article I wrote for the German magazine Zeit Wissen: with the 13 triangular and square pieces (fig. 1) it is possible to form two large squares shown in fig. 2. Though the second large square has an extra piece the dimensions of the squares seem to be the same! Can you explain why this is possible?

This puzzle is available as greeting cards from my online store.

Moona Lisa

In 1997, I remixed the Leonardo da Vinci’s famous painting Mona Lisa into 142 perfectly spaced color beads placed at the intersections of an imaginary two-dimensional triangular network. Close up, the picture of the set of beads makes no sense, but if you see it from a distance you will perceive (or at least ‘guess’?) the portrait of Mona Lisa, the most famous Leonardo Da Vinci’s painting.

hidden mona lisa
Hidden Mona Lisa (1997), © Gianni A. Sarcone