Monochrome
Encyclopedia
Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited color
Color
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...

s or hue
Hue
Hue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...

s. Images using only shades of grey (with or without black and/or white) are called grayscale
Grayscale
In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information...

 or black-and-white
Black-and-white
Black-and-white, often abbreviated B/W or B&W, is a term referring to a number of monochrome forms in visual arts.Black-and-white as a description is also something of a misnomer, for in addition to black and white, most of these media included varying shades of gray...

. However, scientifically speaking, "Monochromatic light" refers to light of a narrow 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...

.

Application

For an image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...

, the term monochrome is usually taken to mean the same as black and white or, more likely, grayscale
Grayscale
In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information...

, but may also be used to refer to other combinations containing only tones of a single color, such as green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...

-and-white or green-and-black. It may also refer to sepia displaying tones from light tan to dark brown or cyanotype
Cyanotype
Cyanotype is a photographic printing process that gives a cyan-blue print. The process was popular in engineering circles well into the 20th century. The simple and low-cost process enabled them to produce large-scale copies of their work, referred to as blueprints...

 (“blueprint”) images, and early photographic methods such as daguerreotypes, ambrotypes, and tintype
Tintype
Tintype, also melainotype and ferrotype, is a photograph made by creating a direct positive on a sheet of iron metal that is blackened by painting, lacquering or enamelling and is used as a support for a collodion photographic emulsion....

s, each of which may be used to produce a monochromatic image.

In computing, monochrome has two meanings:
  • it may mean having only one color which is either on or off,
  • allowing shades of that color, although this is more correctly known as grayscale.


A monochrome computer display
Monochrome monitor
A monochrome monitor is a type of CRT computer display which was very common in the early days of computing, from the 1960s through the 1980s, before color monitors became popular. They are still widely used in applications such as computerized cash register systems...

 is able to display only a single color, often green, amber
Amber (color)
Amber is an orange-yellow color that got its name from the material known as amber. Due to this, amber can refer not to one but to a series of shades of orange, since the natural material varies from nearly yellow when newer to orange or reddish-orange when older.-Amber:Amber is a pure chroma color...

, red
Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...

 or white, and often also shades of that color.

In film photography, monochrome is typically the use of black-and-white film.
Originally, all photography was done in monochrome
Monochrome photography
Monochrome photography is photography where the image produced has a single hue, rather than recording the colours of the object that was photographed. It includes all forms of black-and-white photography, which produce images containing tones of grey ranging from black to white. Most modern...

 until the invention of color film plates in the early 20th century.

In digital photography
Digital photography
Digital photography is a form of photography that uses an array of light sensitive sensors to capture the image focused by the lens, as opposed to an exposure on light sensitive film...

, monochrome is the capture of only shades of black by the sensor, or by post-processing a color image to present only the perceived brightness by combining the values of multiple channels (usually red, blue, and green). The weighting of individual channels may be selected to achieve a desired artistic effect – if only the red channel is selected by the weighting then the effect will be similar to that of using a red filter on panchromatic film. If the red channel is eliminated and the green and blue combined then the effect will be similar to that of Orthochromatic
Orthochromatic
- Orthochromatic photography :Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker...

 film or the use of a cyan filter on panchromatic film. The selection of weighting thus allows a wide range of artistic expression in the final monochromatic image.

For production of an anaglyph image
Anaglyph image
Anaglyph images are used to provide a stereoscopic 3D effect, when viewed with glasses where the two lenses are different colors, such as red and cyan. Images are made up of two color layers, superimposed, but offset with respect to each other to produce a depth effect...

 the original color stereogram
Stereogram
A stereogram is pair of two-dimensional panels depicting the view of a scene or an object from the vantage points of the right and left eyes. Observing the panels superimposed in a stereoscope results in the experience of three-dimensionality by virtue of the fact that object depth is encoded as...

 source may first be reduced to monochrome in order to simplify the rendering of the image. This is sometimes required in cases where a color image would render in a confusing manner given the colors and patterns present in the source image and the selection filters used (typically red
Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...

 and its complement
Complementary color
Complementary colors are pairs of colors that are of “opposite” hue in some color model. The exact hue “complementary” to a given hue depends on the model in question, and perceptually uniform, additive, and subtractive color models, for example, have differing complements for any given color.-...

, cyan
Cyan
Cyan from , transliterated: kýanos, meaning "dark blue substance") may be used as the name of any of a number of colors in the blue/green range of the spectrum. In reference to the visible spectrum cyan is used to refer to the color obtained by mixing equal amounts of green and blue light or the...

).

Theory

In physics, monochromatic refers to electromagnetic radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

 of a single frequency. In the physical sense, no source of electromagnetic radiation is purely monochromatic, since that would require a wave of infinite duration as a consequence of the Fourier transform's localization property (cf. spectral coherence). Even very controlled sources such as laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

s operate in a range of frequencies (known as the spectral linewidth
Spectral linewidth
The spectral linewidth characterizes the width of a spectral line, such as in the electromagnetic emission spectrum of an atom, or the frequency spectrum of an acoustic or electronic system...

). In practice, filtered light, diffraction grating
Diffraction grating
In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as...

 separated light and laser light are all routinely referred to as monochromatic. Often light sources can be compared and one be labeled as “more monochromatic” (in a similar usage as monodispersity). And a device which isolates light sources of a narrow bandwidth are called monochromator
Monochromator
A monochromator is an optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input...

s, even though the bandwidth is often explicitly specified, and thus a collection of frequencies is understood.

See also

  • Duotone
    Duotone
    Duotone is a halftone reproduction of an image using the superimposition of one contrasting color halftone over another color halftone. This is most often used to bring out middle tones and highlights of an image...

     – the use of two ink colors in printing
  • Halftone
    Halftone
    Halftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size, in shape or in spacing...

     – the use of black and white in a pattern that is perceived
    Perception
    Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...

     as shades of grey (may be extended also to color images)
  • Polychrome
    Polychrome
    Polychrome is one of the terms used to describe the use of multiple colors in one entity. It has also been defined as "The practice of decorating architectural elements, sculpture, etc., in a variety of colors." Polychromatic light is composed of a number of different wavelengths...

     – of multiple colors, the opposite of monochrome
  • Monochromacy (color blindness)
  • Selective color
    Selective color
    Selective color is a post-processing technique where most of a photo is converted to black and white, but some parts are left in color. This is usually achieved by using layers and masks in photo editing software .A common application for selective color is portraiture, to keep the eyes and...

     – use of monochrome and color selectively within an image
  • Monochrome painting
    Monochrome painting
    Monochromatic painting has been an important component of avant-garde visual art throughout the 20th century and into the 21st century. Painters have created the exploration of one color, the examination of values changing across a surface, the expressivity of texture and nuance, expressing a wide...

    – monochromes in art
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