The perception of color is strongly influenced by the surrounding colors. This is an optical illusion that can make the same color look strikingly different depending on what colors are around it. Understanding this effect is important for artists, designers, photographers and anyone who works with color.
How does surrounding color affect perception?
The surrounding colors provide a context that the visual system uses to calibrate the appearance of a focal color. This calibration adjusts for different ambient lighting conditions. For example, white under reddish indoor lighting looks white, even though the light itself is reddish. The visual system automatically discounts the reddish cast. Surrounding colors work the same way. Orange surrounded by blues looks brighter and more saturated than the same orange surrounded by reds. This illusion of contrast enhancement occurs because the eyes adapt to the context.
Simultaneous contrast
The contrast illusion was first systematically studied by Michel Eugène Chevreul in the 1830s. He called it “simultaneous contrast”. This refers to the fact that the illusion depends on seeing both colors at the same time. Look at the example below. The inner orange squares are physically identical. However, the one on the blue background looks noticeably different from the one on the red background.
| Orange square on blue | Orange square on red |
|---|---|
| Looks more saturated and brighter | Looks dull and desaturated |
The strong blue makes the inner orange look more vibrant. The strong red makes the inner orange look boring and grayish. This illusion occurs because the visual system automatically enhances contrasts.
Color constancy
Simultaneous contrast is closely related to a phenomenon called “color constancy”. This refers to the fact that the perceived color of an object remains relatively constant under different lighting conditions. For example, a white sheet of paper looks white regardless of whether it is inside under incandescent lights, or outside under blue daylight. This is partly because the visual system adjusts the perceived color based on the surroundings.
Color constancy enhances the stability and accuracy of color perception. Simultaneous contrast arises from the same underlying mechanisms. It causes systematic biased errors in order to maintain constancy under varied viewing conditions.
Contrast effects on value and hue
Surrounding colors influence the perceived lightness and chromaticity of a focal color. Here are some general principles:
- Surrounding light colors make a focal color look darker and more saturated.
- Surrounding dark colors make a focal color look lighter and desaturated.
- Surrounding colors with high chroma increase the focal color’s perceived chroma.
- Surrounding colors on the opposite side of the color wheel make the focal color look tinted toward the opposite hue.
However, these effects are complex and depend on the exact colors involved. Contrast effects can influence all three dimensions of color appearance: lightness, chroma and hue.
Practical use in design
Simultaneous contrast is important in various fields including painting, photography, cinematography, fashion and interior design. Colors always appear in a context. Smart use of contrast effects can enhance or subdue a color:
- Surround with white or dark neutrals to make a color “pop”.
- Surround with harmonious hues to promote a seamless color scheme.
- Surround with adjacent colors on the wheel to subdue through hue cancellation.
- Surround with complementary colors to make both seem more vibrant.
Many stylistic hallmarks of modern design can be explained by contrast effects. Large fields of bold saturated colors create vibrancy. Black and white paired with strong colors enhances their brilliance. Complementary colors surrounded by neutrals appear more intense. Monochromatic palettes lend sophistication through subtle hue contrasts.
Illusions of transparency & color mixing
Contrast effects influence not just surface colors, but also transparency and color mixing. In watercolor painting, areas left unpainted look whiter or lighter than the bare paper. Transparent glazes appear more saturated next to white space. And combining paints on the palette results in different colors than mixing them directly on the paper. The same general principles apply in computer graphics and digital image editing.
Mechanisms in the visual system
Current models propose that simultaneous contrast occurs at multiple levels of visual processing. Initial opponent interactions in the retina and LGN adapt to the surrounding color. Later processing in cortical area V1 extracts borders and spatial variations in color. Higher extrastriate areas integrate spatial color patterns and perform statistical computations to infer surface colors. Top-down feedback circuits carry contextual information to lower levels.
Neural mechanisms for color constancy serve to stabilize color appearance across scenes and lighting conditions. Contrast effects reflect the spatial comparisons the visual system uses to recalibrate colors in context. Illusory contrast enhances differences between adjacent areas at the expense of accuracy.
Individual differences in susceptibility
Simultaneous contrast illusions work on most people. However, some studies have found significant individual differences in susceptibility. People seem to vary in the degree to which surrounding colors affect their perception. Less susceptible individuals show weaker contrast effects. But the mechanisms causing this variation remain unclear.
Differences are thought to depend on neural factors like lateral inhibition and neural adaptation. Short-term sensory adaptation to the surround may play a role. Subjects also seem to differ in how rapidly they adjust to changes in contextual colors when alternating between displays. This points to possible higher-level effects.
Contrast effects across sensory domains
Contrast effects are not limited just to color. Similar phenomena occur in other sensory channels. In audition, surrounding sounds affect the perceived loudness of a tone at a given frequency. In gustation, the perceived intensity of flavors depends on what other tastes are present. And in somatosensation, skin pressure feels different based on stimuli applied to surrounding areas.
In all cases, contrast arises from lateral inhibitory interactions between adjacent receptive fields in the sensory pathways. Surround suppression sharpens representations of edges and spatial variations in intensity. Perceptual contrast enhances processing of local stimulus differences.
Illusions of brightness & lightness
Black, white and grays also induce contrast effects on each other. The same gray can look much darker or lighter depending on its surround. Lightness illusions underlie many popular optical illusions. The Mach bands illusion and many variants exploit how contrast affects perceived brightness.
These luminance contrast effects likely arise from neural circuits in the retina and LGN. Color simultaneous contrast engage additional cortical mechanisms specialized for comparing opponent colors. However, the two phenomena likely share common computational principles for calibrating appearances based on context.
History & early observations
Contrast effects were first noted in visual art and physiology in the early 1800s. Goethe, Schopenhauer, Chevreul and others described how colors look different against different backgrounds. Ewald Hering systematically studied how surrounding colors affect hue in the late 1800s. These observations were early insights into color appearance mechanisms.
James Clerk Maxwell helped explain contrast effects in 1850s. He noted they depend on simultaneous comparisons of adjacent areas through lateral inhibition between retinal receptors. Spatial interactions enable color constancy but also produce illusions. Opponent process theories further refined neural models of contrast in the 1950s-60s.
Contrast in art media & design
Simultaneous contrast poses challenges in realistic fine art media aiming to faithfully reproduce appearances. Painters must compensate so colors look accurate and constant. Otherwise, illusion distorts perception of surface colors.
Sophisticated techniques of optical color mixing help achieve constancy. Georges Seurat developed pointillism to control interactions through spacing. Impressionists exploited contrast to enhance chromatic vibration with pure juxtapositions. Modern color field painting reverses figure-ground to make color itself the subject.
In abstract graphic design, simultaneous contrast becomes an expressive tool. Complementary contrast creates dynamic tension. Restricted palettes allow subtle interplay between neighboring hues. Vibrant accent colors can draw attention by contrast with neutrals.
Knowledge of contrast mechanisms informs wider practices in design fields. Interior designers arrange wall colors to brighten a space. Landscape architects plant flowers for seasonal highlights. Fashion designers set patterns and accessories against neutrals. In all cases, context changes appearances.
Conclusion
In summary, simultaneous contrast provides a vivid demonstration of how color perception depends on context. Surrounding colors have a potent influence on how humans see focal colors. Contrast effects likely serve to optimize sensitivity to spatial variations in the environment. But these adaptive mechanisms also give rise to compelling illusions.
Understanding contrast phenomena remains important for both basic research and applied design. The visual system evolved to extract relations and contrasts, not just surface colors. Perception is a constructive process that aims for meaningful representations rather than just passive recordings. Context determines color and contrast determines perception.
