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Darkness, the direct opposite of lightness, is defined as a lack of illumination, an absence of visible
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...
, or a surface that absorbs light, such as black or brown. Human
vision Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...
is unable to distinguish
color Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are assoc ...
s in conditions of very low luminance. This is because the
hue In color theory, hue is one of the main properties (called color appearance parameters) of a color, defined technically in the CIECAM02 model as "the degree to which a stimulus can be described as similar to or different from stimuli that ...
sensitive photoreceptor cells on the
retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
are inactive when light levels are insufficient, in the range of visual perception referred to as
scotopic vision In the study of human visual perception, scotopic vision (or scotopia) is the vision of the eye under low-light conditions. The term comes from Greek ''skotos'', meaning "darkness", and ''-opia'', meaning "a condition of sight". In the human eye, ...
. The emotional response to darkness has generated
metaphor A metaphor is a figure of speech that, for rhetorical effect, directly refers to one thing by mentioning another. It may provide (or obscure) clarity or identify hidden similarities between two different ideas. Metaphors are often compared wi ...
ical usages of the term in many cultures, often used to describe an unhappy or foreboding feeling. Referring to a time of day, complete darkness occurs when the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
is more than 18° below the horizon, without the effects of
twilight Twilight is light produced by sunlight scattering in the upper atmosphere, when the Sun is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this i ...
on the
night sky The night sky is the nighttime appearance of astronomical object, celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon. Natural light sources in a ...
.


Scientific


Perception

The perception of darkness differs from the mere absence of light due to the effects of after images on perception. In perceiving, the eye is active, and the part of the retina that is unstimulated produces a complementary afterimage.


Physics

In terms of physics, an object is said to be dark when it absorbs photons, causing it to appear dim compared to other objects. For example, matte black paint does not reflect much visible light and appears dark, whereas white paint reflects much light and appears bright. For more information, see
color Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are assoc ...
. An object may appear dark, but it may be bright at a frequency that humans cannot perceive. A dark area has limited light sources, making things hard to see. Exposure to alternating light and darkness (night and day) has caused several evolutionary adaptations to darkness. When a
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
, like a human, enters a dark area, its
pupils The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black ...
dilate, allowing more light to enter the eye and improving night vision. Also, the light detecting cells in the human eye (
rods and cones A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiati ...
) will regenerate more unbleached rhodopsin when adapting to darkness. One scientific measure of darkness is the Bortle Dark-Sky Scale, which indicates the night sky's and stars' brightness at a particular location, and the observability of celestial objects at that location. (See also: Sky brightness) The material known as Vantablack is one of the darkest substances known, absorbing up to 99.965% of visible light (at 663 nm if the light is perpendicular to the material) is a material developed by Surrey NanoSystems in the United Kingdom. The name is a compound of the acronym VANTA (vertically aligned nanotube arrays) and the color black.


Technical

The color of a pixel, point, on a standard 24-bit computer display, is defined by three RGB (red, green, blue) values, each ranging from 0–255. When the red, green, and blue components of a pixel are fully illuminated (255,255,255), the pixel appears white; when all three components are unilluminated (0,0,0), the pixel appears black.


Cultural


Artistic

Artists use darkness to emphasize and contrast the presence of light. Darkness can be used as a counterpoint to areas of lightness to create Composition (visual arts)#Line and shape, leading lines and negative space, voids. Such shapes draw the eye around areas of the painting. Shadows add depth and perspective to a painting. See chiaroscuro for a discussion of the uses of such contrasts in visual media. Color paints are mixed together to create darkness, because each color absorbs certain frequencies of light. Theoretically, mixing together the three primary colors, or the three secondary colors, will absorb all visible light and create black. In practice it is difficult to prevent the mixture from taking on a brown tint.


Literature

As a poetic term in the Western world, darkness is used to connote the presence of shadows, evil, and foreboding, or in modern parlance, to connote that a story is grim, heavy, and/or depressing.


Religion

The first creation narrative in Judaism and Christianity begins with darkness, into which is introduced the creation of light, and the separation of this light from the darkness (as distinct from the creation of the sun and moon on the fourth day of creation). Thus, although both light and darkness are included in the comprehensive works of the almighty God—darkness was considered "the second to last plague" (Book of Exodus, Exodus 10:21), and the location of "weeping and gnashing of teeth" (Gospel of Matthew, Matthew 8:12). Erebus was a Greek primordial deities, primordial deity in Greek mythology, representing the personification of darkness.


Philosophy

In Chinese philosophy, Yin and yang, Yin is the complementary feminine part of the Taijitu and is represented by a dark lobe.


Poetry

The use of darkness as a rhetorical device has a long-standing tradition. Shakespeare, working in the 16th and 17th centuries, made a character called the "prince of darkness" (King Lear: III, iv) and gave darkness jaws with which to devour love. (A Midsummer Night's Dream: I, i) Chaucer, a 14th-century Middle English writer of ''The Canterbury Tales'', wrote that knights must cast away the "workes of darkness". In ''The Divine Comedy'', Dante described hell as "solid darkness stain'd".


Language

In Old English there were three words that could mean darkness: ''heolstor'', ''genip'', and ''sceadu''. ''Heolstor'' also meant "hiding-place" and became holster. ''Genip'' meant "mist" and fell out of use like many Germanic strong verb, strong verbs. It is however still used in the Dutch language, Dutch saying "in het geniep" which means secretly. ''Sceadu'' meant "shadow" and remained in use. The word ''dark'' eventually evolved from the word ''deorc''.


See also

*Lightness *Shadow *Theory of colours


References


External links

* * * {{Goth subculture Darkness, Blindness