Bezold effect is an Optical illusion named after a German professor Wilhelm Von Bezold, who stated that a color may appear different depending on its relation to adjacent colors around it.

We all have heard about the term ‘Optical illusion’. An optical illusion/Visual illusion is termed as the falsified imagery caused by our visual system and is characterized by a visual perception that appears to be quite different from reality. Illusions may come up in a wide variety and sometimes their categorization seems difficult. This is because of the fact that the underlying cause of the illusion is often not so clear. However, a classification was proposed by Sir Richard Gregory and this classification is useful in case of considering the orientation.

According to the classification laid by Sir Richard Gregory, there are 3 main divisions of classes :

–           Physical illusions

–           Physiological illusions

–           Cognitive illusions

The most explained example of a physical illusion can be the apparent bending of a stick when it is half immersed in water. The Cognitive types of visual illusions are the results of unconscious inferences and this class is perhaps the one that is most widely known.


The Bezold effect is a kind of optical illusion that was named after a German professor of Meteorology, Sir Wilhelm Von Bezold; who discovered that the colors may appear to be different depending on its relation to the adjacent colors. According to Sir Wilhelm Von Bezold, this happens when small areas of the color are interspersed. Additionally, an assimilation effect which is called the Von Bezold Spreading effect is observed which is just similar to the spatial color mixing.

An opposite effect of this effect is observed when large areas of color are placed just adjacent to each other, which results in the color contrast.

Bezold Effect is also referred to as the “Assimilation Effect” since it is an optical illusion where the hue (dominant spectral color) or value (lightness or the darkness) of the color is affected by the color or colors that are surrounding it. Bezold discovered that, in contrast to the already established findings of the simultaneous color contrast in which color usually takes on the complementary hue and the brightness that is in contrast of its surroundings, Bezold also discovered that in a certain type of situations, a colored region may take up the same color as that of its surrounding.


When we are looking at a specific hue of any spectral color, then we can see that it appears to change its appearance depending on the colors that are surrounding it. For instance, a Yellow box that is surrounded by Blue color will look darker as compared to a Yellow box surrounded by the Red color. In most cases, it is observed that the surrounded color seems to take on a slight tint of the color that surrounds it. Here the red boxes that were surrounded by the blue one will appear to be more bluish than the ones surrounded by white. The clearest demonstration of this effect is when two patches of almost identical color are surrounded by thin black and white borders respectively. The one that is surrounded by black will appear to be a bit darker than the one surrounded by the white. These colored regions assimilate their border color. The opposite of the contrast effect is often found related to brightness, and also with hue.

The main reason behind the Bezold effect still remains to be a neurological puzzle. Although it is to be noted here that the interactions of the color in the form of simultaneous color contrast effects could be easily and effectively explained by some inhibition and excitation functions in the field of color perception.


The knowledge of the Bezold effect is very useful in fields such as graphic design, specifically where the artists can use any number of combinations of all the present adjacent colors to create the effect that they desire to suit their design. They can even mix and match the various effects and according to their creativity, they can create a new one.

According to Albers, the Bezold effect is a special kind of optical mixture. Albers also described in his book that Bezold recognized this effect while he was searching for a method through which he could change the color combinations in one of his rug designs totally; by adding or changing one color only. But till now, there is no much clear recognition of the optical perceptual conditions that were involved here. In fact, the Albers’ Theory of color relativity can be considered as a good expansion on the Bezold effect principles. Johannes Itten, one of the Albers’ colleagues, again framed up the principle in identifying some useful simultaneous contrast afterward as well.


The Bezold Effect in simple terms revolves around the substitution of a single color; which may cause every other color in the design to shift in other relationships. Changing just one color in design tends to change the entire design in terms of its composition, personality, spatial perception, and sometimes even in its weight.

When one color is changed, the relationship that exists between all the colors in the design is changed. It is important to understand here that the color relationships do not show an even change. Thus, some colors will appear slightly lighter, or some slightly darker, while the others may appear significantly darker or lighter, or more saturated, or they may be de-saturated as well. If anyone wants a lot of energy in the design, they can undergo some color substitutions until they achieve the amount of desired activity that they require.

The Bezold effect helps a lot in case anyone wants to balance a large area of dark or heavy colors or use a small amount of bright or light color. It also plays a huge role if we want to focus the attention on a particular element in the design.

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