Optical Illusions
Perceptual illusion caused by contextual lines
Retinal Afterimage
Mona Lisa (Negative Image), Leonardo da Vinci
Fixate on the nose of the Mona Lisa for about 5 seconds, then look at the black dot on the right.
Mona Lisa, Leonardo da Vinci
Here, the afterimage is the negative image of the previous one. The afterimage effect occurs in everyday life with every shift of gaze. However, it is rarely noticed, as gaze shifts typically happen at a high frequency, and monochrome surfaces are rare in everyday life.
The three primary colors stacked vertically, with their respective complementary color placed to the right. The colors of afterimages are always the complementary colors of the original. Therefore, the afterimage on the right is mirrored in terms of colors.
The afterimage effect can also be used to create a dynamic effect, as shown here in a schematic example. The pure black nodes of the grid pattern appear as a white circle with a black border due to the afterimage. To observe the real afterimage, fixate on the center of the grid pattern and then look at the black dot on the right side.
Eine optische Täuschung: Der graue Balken ist monochrom, er besitzt überall dasselbe Grau. Diese optische Täuschung verdeutlicht den Simultankontrast als eines der Prinzipien der Malerei: Ein und dieselbe Farbe wirkt vor einer helleren Farbe dunkler und vor einer dunkleren Farbe heller. Die Helligkeit einer Farbe richtet sich nach ihren Grauwert.
Association with the nose
Looking to the left reveals the right half of the nose, here shown with an exaggerated depiction of a button nose. If the gaze quickly shifts back and forth to the left, for example, due to external stimuli, a dancing movement is created through the afterimage effect (Mouseover).
Looking to the right reveals the left half of the nose, here shown with an exaggerated depiction of a button nose. If the gaze quickly shifts back and forth to the right, for example, due to external stimuli, a dancing movement is created through the afterimage effect (Mouseover).
When the focus of the eyes is directed at a nearby object, the left and right nostrils appear as one image. If the focus of the eyes changes at regular intervals, for example, due to rhythmic shifts between near and far vision, light stimuli, fatigue, drug influence, or increased pulse from physical activities, the nostrils form an interesting and difficult-to-capture dynamic afterimage. Here, with a frequency of 120 per minute (Mouseover).
When looking downward, the nostrils form two characteristic lines that taper downward. The lower boundary is defined by the cheeks. To clarify, a view of a very close object has been simulated here, which brings the nostrils even closer together.
When looking upwards, the nostrils, together with the upper part of the nose, form a heart. The top point is formed by the overlapping eyebrows. When looking against the sun, a rainbow appears at that spot, caused by light reflections from hair oils or evaporating sweat (Mouseover).
Depending on the browser version used, the painting may not be displayed correctly.
When the focus of the eyes is directed at a slightly more distant object, the left and right nostrils also appear as one image, but the frame of the image changes. Below, the lines of the cheeks, above, the lines of the overlapping eyebrows.
Uses in painting
The arch-shaped wave rises in a semicircle on the left side of the painting and seems to break above Japan’s highest mountain, Mount Fuji (in the background)
Magnificent flowers in vases are a common motif in painting. Characteristic is the typical contour of the vase and flowers, which viewers perceive as particularly aesthetic
The twelve angels on the left side are arranged as a mirror image to the nine angels on the right side. In the lower part a gap separates the two groups from each other
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