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Darkness, the direct opposite of
lightness Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a stan ...
, is defined as a lack of illumination, an absence of visible light, or a surface that absorbs light, such as black or brown. Human vision is unable to distinguish colors in conditions of very low
luminance Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls withi ...
. This is because the hue sensitive
photoreceptor cell 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 radiatio ...
s on the retina are inactive when light levels are insufficient, in the range of visual perception referred to as scotopic vision. The emotional response to darkness has generated metaphorical 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 is more than 18° below the
horizon The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether i ...
, without the effects of twilight on the night sky.


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 A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they alway ...
, 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. 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, like a human, enters a dark area, its pupils dilate, allowing more light to enter the eye and improving
night vision Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vi ...
. Also, the light detecting cells in the human eye ( rods and cones) will regenerate more unbleached
rhodopsin Rhodopsin, also known as visual purple, is a protein encoded by the RHO gene and a G-protein-coupled receptor (GPCR). It is the opsin of the rod cells in the retina and a light-sensitive receptor protein that triggers visual phototransduction ...
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 Sky brightness refers to the visual perception of the sky and how it scatters and diffuses light. The fact that the sky is not completely dark at night is easily visible. If light sources (e.g. the Moon and light pollution) were removed fro ...
) 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 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 leading lines and 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" (
Exodus Exodus or the Exodus may refer to: Religion * Book of Exodus, second book of the Hebrew Torah and the Christian Bible * The Exodus, the biblical story of the migration of the ancient Israelites from Egypt into Canaan Historical events * Exo ...
10:21), and the location of "weeping and gnashing of teeth" ( Matthew 8:12). Erebus was a primordial deity in Greek mythology, representing the personification of darkness.


Philosophy

In Chinese philosophy,
Yin Yin may refer to: *the dark force in the yin and yang from traditional Chinese philosophy and medicine *Yīn (surname) (), a Chinese surname *Yǐn (surname) (), a Chinese surname *Shang dynasty, also known as the Yin dynasty **Yinxu or Yin, the S ...
is the complementary feminine part of the Taijitu and is represented by a dark lobe.


Poetry

The use of darkness as a
rhetorical device In rhetoric, a rhetorical device, persuasive device, or stylistic device is a technique that an author or speaker uses to convey to the listener or reader a meaning with the goal of persuading them towards considering a topic from a perspective, ...
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 ''A Midsummer Night's Dream'' is a comedy written by William Shakespeare 1595 or 1596. The play is set in Athens, and consists of several subplots that revolve around the marriage of Theseus and Hippolyta. One subplot involves a conflict amon ...
: I, i) Chaucer, a 14th-century Middle English writer of ''
The Canterbury Tales ''The Canterbury Tales'' ( enm, Tales of Caunterbury) is a collection of twenty-four stories that runs to over 17,000 lines written in Middle English by Geoffrey Chaucer between 1387 and 1400. It is widely regarded as Chaucer's ''Masterpiece, ...
'', 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 Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...
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 strong verbs. It is however still used in the 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 Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a stan ...
* Shadow * Theory of colours


References


External links

* * * {{Goth subculture Blindness