Darkness
Encyclopedia
Brightness
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target...
, is a relative absence of visible light. It is the appearance of black
Black
Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light...
in a color space. When light is not present, rod
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
and cone cell
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s within the eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
are not stimulated. This lack of stimulation means photoreceptor cells are unable to distinguish color frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
and wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
. The resulting perception is achromatic and in the case of darkness, black. The emotional reaction to darkness has metaphorical importance in many cultures.
Scientific
A dark object absorbs photons, and therefore appears dim in comparison to other objects. For example, matte black paint does not reflect visible light and appears dark, but white paint reflects all visible light and appears bright. For more information see colorColor
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
.
However, light cannot simply be absorbed without limit. Energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
, like visible light, cannot be created or destroyed. It can only be converted from one type of energy to another. Most objects that absorb visible light reemit it as infrared light. So, although an object may appear dark, it is likely bright at a frequency that a human being cannot see. For more information see thermodynamics
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
.
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
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
, like a human, enters a dark area, its iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
dilates, allowing more light to enter the eye and improving night vision
Night vision
Night vision is the ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range...
. Also, the light detecting cells in the human eye (rods and cones) will regenerate more unbleached rhodopsin
Rhodopsin
Rhodopsin, also known as visual purple, is a biological pigment of the retina that is responsible for both the formation of the photoreceptor cells and the first events in the perception of light. Rhodopsins belong to the G-protein coupled receptor family and are extremely sensitive to light,...
when adapting to darkness.
One scientific measure of darkness is the Bortle Dark-Sky Scale
Bortle Dark-Sky Scale
The Bortle Dark-Sky Scale is a nine-level numeric scale that measures the night sky's and stars' brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution and skyglow. John E...
, 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
The fact that the sky is not completely dark at night can be easily observed. Were the sky absolutely dark, one would not be able to see the silhouette of an object against the sky....
)
Cultural
Poetic
As a poetic term in the Western worldWestern world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...
, darkness can also mean the presence of shadows, evil, or depression.
Religious texts often use darkness to make a visual point. In the Bible
Bible
The Bible refers to any one of the collections of the primary religious texts of Judaism and Christianity. There is no common version of the Bible, as the individual books , their contents and their order vary among denominations...
, darkness was the second to last plague (Exodus 10:21) and the location of “weeping and gnashing of teeth.” (Matthew 8:12) The Qur’an has been interpreted to say that those who transgress the bounds of what is right are doomed to “burning despair and ice-cold darkness.” (Nab 78.25)
In Chinese philosophy
Chinese philosophy
Chinese philosophy is philosophy written in the Chinese tradition of thought. The majority of traditional Chinese philosophy originates in the Spring and Autumn and Warring States era, during a period known as the "Hundred Schools of Thought", which was characterized by significant intellectual and...
Yin is the feminine part of the Taijitu
Taijitu
Taijitu is a term which refers to a Chinese symbol for the concept of yin and yang...
and is represented by a dark lobe.
The use of darkness as a rhetorical device
Rhetorical device
In rhetoric, a rhetorical device or resource of language is a technique that an author or speaker uses to convey to the listener or reader a meaning with the goal of persuading him or her towards considering a topic from a different perspective. While rhetorical devices may be used to evoke an...
has a long standing tradition. Shakespeare, working in the 16th and 17th centuries, made a character called Satan, the “prince of darkness
Prince of Darkness
Prince of Darkness is a box set of four CDs by Ozzy Osbourne released in 2005. The first two CDs are Osbourne's solo work containing various studio recordings, live tracks, b-sides, demos and outtakes, and the last two CDs are duets on disc three and cover songs on disc four...
” (King Lear
King Lear
King Lear is a tragedy by William Shakespeare. The title character descends into madness after foolishly disposing of his estate between two of his three daughters based on their flattery, bringing tragic consequences for all. The play is based on the legend of Leir of Britain, a mythological...
: 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, wrote that knights must cast away the “workes of darkness.” Dante described hell as “solid darkness stain’d.”
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 strong verb
Germanic strong verb
In the Germanic languages, a strong verb is one which marks its past tense by means of ablaut. In English, these are verbs like sing, sang, sung...
s. It is however still used in the Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...
saying "in het geniep" which means secretly. Sceadu meant “shadow” and remained in use. The word dark eventually evolved from the word deorc.
Artistic
Artistically, darkness can also be used to emphasize or contrast with light. See chiaroscuro
Chiaroscuro
Chiaroscuro in art is "an Italian term which literally means 'light-dark'. In paintings the description refers to clear tonal contrasts which are often used to suggest the volume and modelling of the subjects depicted"....
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.
The color of a point
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
, on a standard 24-bit computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
, is defined by three numbers between 0 and 255, one each for red, green, and blue. Because the absence of light creates darkness, darker colors are closer to (0,0,0).
Paintings may use darkness to create leading lines and voids, among other things. These shapes are designed to draw the eye around the painting. Shadows add perspective.
See also
- Lightness (color)Lightness (color)Lightness is a property of a color, or a dimension of a color space, that is defined in a way to reflect the subjective brightness perception of a color for humans along a lightness–darkness axis. A color's lightness also corresponds to its amplitude.Various color models have an explicit term for...
- Dark tourismDark tourismDark tourism is tourism involving travel to sites associated with death and suffering. Thanatourism, derived from the Ancient Greek word thanatos for the personification of death, is associated with dark tourism but refers more specifically to violent death; it is used in fewer contexts than the...
- travelTravelTravel is the movement of people or objects between relatively distant geographical locations. 'Travel' can also include relatively short stays between successive movements.-Etymology:...
to sites associated with deathDeathDeath is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
and sufferingSufferingSuffering, or pain in a broad sense, is an individual's basic affective experience of unpleasantness and aversion associated with harm or threat of harm. Suffering may be qualified as physical or mental. It may come in all degrees of intensity, from mild to intolerable. Factors of duration and... - ShadowShadowA shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or reverse projection of the object blocking the...