Color

Color perception and vision

• Color is based on the electromagnetic spectrum
• Color perception is related to light absorption, reflection, emission spectra, and interference
• Humans perceive colors in the visible light spectrum with three types of cone cells (trichromacy)
• Animals may have a different number of cone cell types or different color sensitivity ranges
• Animal perception of color is processed by the brain
• Color vision deficiency causes a limited perception of colors
• Different forms of color blindness result from cone cell anomalies
• Cerebral achromatopsia is caused by neural anomalies in the brain
• Metamerism occurs when colors appear the same to color blind individuals
• Tetrachromacy is present in many vertebrates, allowing for enhanced color discrimination
• Most mammals are dichromatic, while many non-mammals are tetrachromatic
• Some invertebrates, like mantis shrimp, have even more cones for a richer color gamut
• Human tetrachromacy is a debated topic, with some individuals potentially having four cone classes
• Functional tetrachromats may be able to perceive up to a hundred million colors
• Synesthesia can cause the perception of color in response to letters, numbers, or sounds
• Behavioral and neuroimaging experiments support the reality of synesthetic color experiences
• Synesthesia leads to changes in behavioral tasks and increased activation of color perception brain regions
• Similarity between synesthetic color percepts and real color perception
• Synesthesia provides a non-standard route to experiencing color
• Photoreceptors become desensitized after exposure to strong light
• Afterimages occur when the eye continues to see a bright figure after looking away from it
• Afterimages appear in complementary colors
• Afterimage effects have been used by artists, including Vincent van Gogh
• Human eye compensates for limited color palettes by seeing gray or neutral colors as the missing color
• Trichromatic theory is true when the visual system is in a fixed state of adaptation
• Visual system constantly adapts to changes in the environment and compares colors to reduce the effects of illumination
• Edwin H. Land studied color constancy and proposed the retinex theory
• Chromatic adaptation and color appearance theories explain afterimage effects

Color properties and perception

• Spectral colors are those produced by visible light of a single wavelength
• Spectral colors have 100% purity and are fully saturated
• The division of spectral colors into distinct categories is influenced by culture and history
• The inclusion or exclusion of colors like indigo and cyan is a topic of debate
• The intensity of a spectral color can alter its perception
• The color of an object depends on how it absorbs and scatters light
• Transparent objects are perceived as colorless because they allow light to transmit through
• Opaque objects do not transmit light and instead absorb or reflect it
• Translucent objects appear colored because they scatter or absorb specific wavelengths of light
• Absorbed light in objects is often dissipated as heat
• Color reproduction aims to create colors that faithfully represent the desired color for the human eye
• Most colors are mixtures of various wavelengths of light, not spectral colors
• Dominant wavelength is used to describe non-spectral colors
• Metamers are different light spectra that have the same effect on the three color receptors in the human eye
• Color reproduction methods or color spaces use three specific primary colors
• Additive color mixing involves combining light of different colors
• Red, green, and blue are the additive primary colors
• Additive color systems are used in projectors, televisions, and computer terminals
• Subtractive color mixing involves combining dyes, inks, pigments, or filters
• Subtractive coloring absorbs some wavelengths of light and reflects others
• The color displayed by a surface comes from the parts of the visible spectrum that are not absorbed
• Subtractive coloring uses twelve main pigment colors
• Pigments or inks subtract or absorb specific wavelengths of light to create different colors

Color terminology and research

• Colors vary in hue, saturation, and brightness
• Color words can be derived from objects or abstract concepts
• Basic color terms follow a pattern of evolution and universality
• Lists of colors and web colors exist for reference
• Color technology and physics are studied in relation to color
• Research on structural color has been conducted since Isaac Newton and Robert Hooke
• Electron micrography has advanced the study of structural color
• Color perception is influenced by the eye and brain
• Specialized color modules exist in the macaque extrastriate cortex
• Color preference is spatially clustered in certain areas of the brain

Cultural and symbolic meanings of color

• Colors and their meanings play a role in art and literature
• Color psychology studies the effects of color on human emotion and activity
• Chromotherapy is an alternative medicine based on color
• Colors have different associations in different countries and cultures
• Red decreases cognitive functioning in men, according to a study
• Colors can have different meanings and associations in different cultures
• For example, in Western cultures, red is often associated with love and passion, while in some Eastern cultures, it symbolizes luck and prosperity
• Colors can also have symbolic meanings, such as yellow representing happiness or blue symbolizing calmness
• The use of color in branding and advertising can evoke certain emotions and associations in consumers
• Different industries may use specific colors in their logos and designs
• Colors have national associations and symbolism
• Different colors have demonstrated effects on cognition
• The combination of red and yellow can induce hunger
• Color affects memory development
• Wearing bright colors makes you more memorable to others

Development of color theories and studies

• Theories of color vision have been developed throughout history
• Newton identified light as the source of color sensation
• Young proposed the trichromatic theory, which states that any color can be matched with a combination of three lights
• Hering developed the opponent process theory

Color Data Sources