Research on Optical Illusions may explain the brilliance of Pointillist Paintings

Pointillism is a painting technique, developed by Georges Seurat and Paul Signac in 1886, in which small, distinct dots of color are applied in patterns to form an image. Inspired by scientific research on optical effects and perception in color theories, Seurat concentrated, in his work, on the issues of color, light, and form. He contrasted miniature colored dots, that when unified optically in the human eye, were perceived as a single shade or hue. Research in the sciences of color, at that time, found that overlapping primary colors would form a third color from a distance. With Seurat, a new artistic movement emerged that took a scientific take on art. In Seurat’s own words: “Some say they see poetry in my paintings, I see only science.”

A Sunday on La Grande Jatte Georges Seurat 1884

A famous example of pointillism is Seurat’s “A Sunday Afternoon on the Island of La Grande Jatte”. The artist spent over two years painting it, focusing meticulously on the landscape of the suburban park, located on an island in the Seine River. The painting is composed of tiny colored dots, making the colors more brilliant and powerful than standard brush strokes. Seurat defines form by close parallel brushstrokes. And to make the perception of the image even more vivid, he surrounded his painting with a frame of painted dots, which in turn he enclosed with a pure white, wooden frame.

extreme closeup seurat sunday afternoon jatte dots

Close-up of the paint on canvas in the Grand Jatte.

On a closer examination, one will notice that the dots in a given region of the painting aren’t all the same color. In the picture above, you can see an extreme close-up of the painting that shows individual dots of contrasting colors. The leaves in the trees range from red to yellow to green to blue, and the water includes blues, purples, greens, and yellows. As odd as this seems, it is quite similar to a digital color printer that places dots of Cyan (blue), Magenta (red), Yellow, and Key (black) or a TV monitor that uses a similar technique to represent image colors using Red, Green, and Blue (RGB) colors.

An observer will also get the impression that the colors actually change as they approach or move away from the work. Vision scientist P. Mamassian believes that what you experience as you view “La Grande Jatte”, might be similar to a visual illusion described in a study by P. Monnier and S. K. Shevell. Take a look at this:

Monnier, Shevell (2003). Large shifts in color appearance from patterned chromatic backgrounds Nature Neuroscience,

The orange/pink rings in the center of each large lime/purple ring appear to all be different colors. But actually they are physically identical. Now compare the difference in appearance between the test rings a and b to the difference between the test rings c and d. The central rings in c and d (with patterned backgrounds) appear to be much different to each other in color than the central rings in a and b (with uniform backgrounds). In (e-h), new patterns were constructed in which one of either purple or lime was replaced with equal-energy white. It was found that the same effect occurs: larger color shifts were observed from patterned (e-h) than uniform backgrounds (a-b). The responses were consistent: everyone with normal color vision appears to experience the illusion. The authors concluded that patterned backgrounds can induce color shifts that are stronger than the shifts from a uniform background, at any chromaticity within the pattern.

It is well documented that the perceived color of a small patch is very much affected by the background. However, the above research has shown that the shift in perceived color of the patch is larger when the background is itself composed of small regions rather than being uniform. This finding might provide a new perspective on pointillist paintings, where numerous small patches of color were preferred over large uniform color regions.

seurat grande jatte detail

This closeup of the “Grande Jatte” shows a good example of the use of small patches of color contrasts in pointillism. Red surfaces are placed next to green ones but a close examination of the painting shows that each surface is itself composed of numerous small patches.

This illusion only occurs at certain visual angles – and this could lead to colors in the Seurat painting appearing to change when our distance to the painting makes the patches appear about the same width as the rings in Monnier’s study.

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