0_Wizard
I like blue because  is one of the three primary colours of pigments in painting and traditional color theory also it's very soft and friendly to the eye
Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model.
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Blue
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Red
Red is the colour at the end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. The red sky at sunset results from Rayleigh scattering, while the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide.
Color theory
In the visual arts, color theory or colour theory is a body of practical guidance to color mixing and the visual effects of a specific color combination. There are also definitions (or categories) of colors based on the color wheel: primary color, secondary color and tertiary color. Although color theory principles first appeared in the writings of Leone Battista Alberti (c.1435) and the notebooks of Leonardo da Vinci (c.1490), a tradition of "colory theory" began in the 18th century, initially within a partisan controversy over Isaac Newton's theory of color ("Opticks", 1704) and the nature of primary colors.
Blue
Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colors; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall scattering explains blue eyes.
Green
Green is the color between blue and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and blue, or yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. By far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy.
Purple
Purple is a color intermediate between blue and red. It is similar to violet, but unlike violet, which is a spectral color with its own wavelength on the visible spectrum of light, purple is a composite color made by combining red and blue. According to surveys in Europe and the U.S., purple is the color most often associated with royalty, magic, mystery and piety. When combined with pink, it is associated with eroticism, femininity and seduction. Purple was the color worn by Roman magistrates; it became the imperial color worn by the rulers of the Byzantine Empire and the Holy Roman Empire, and later by Roman Catholic bishops.
Complementary colors
Complementary colors are pairs of colors which, when combined, cancel each other out. This means that when combined, they produce a gray-scale color like white or black. When placed next to each other, they create the strongest contrast for those particular two colors. Due to this striking color clash, the term opposite colors is often considered more appropriate than "complementary colors". Which pairs of colors are considered complementary depends on the color theory one uses:  On the traditional color wheel developed in the 18th century, used by Claude Monet and Vincent van Gogh and other painters, and still used by many artists today, the primary colors were considered to be red, yellow, and blue, and the primary–secondary complementary pairs are red–green (Christmas), blue-orange (Westwood), and yellow–purple (Mesa High).
Neo-impressionism
Neo-Impressionism is a term coined by French art critic Félix Fénéon in 1886 to describe an art movement founded by Georges Seurat. Seurat’s greatest masterpiece, "A Sunday Afternoon on the Island of La Grande Jatte", marked the beginning of this movement when it first made its appearance at an exhibition of the Société des Artistes Indépendants (Salon des Indépendants) in Paris. Around this time, the peak of France’s modern era emerged and many painters were in search of new methods. Followers of Neo-Impressionism, in particular, were drawn to modern urban scenes as well as landscapes and seashores.
1_Apprentice
Blue is my favourite colour! Van Gogh used much of it in some of my favourite paintings.
0_Wizard
Do you know that blue can be found netween violet and green on the spectrum of visible light.
It lies between violet and green on the spectrum of visible light.
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Blue
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Ultraviolet
Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the total light output of the Sun, and is thus present in sunlight. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although it's not considered an ionizing radiation because its photons lack the energy to ionize atoms, long-wavelength ultraviolet radiation can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.
Fluorescent lamp
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. Fluorescent lamp fixtures are more costly than incandescent lamps because they require a ballast to regulate the current through the lamp, but the lower energy cost typically offsets the higher initial cost.
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. The most striking example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum, and thus invisible to the human eye, while the emitted light is in the visible region, which gives the fluorescent substance a distinct color that can only be seen when exposed to UV light. Fluorescent materials cease to glow immediately when the radiation source stops, unlike phosphorescence, where they continue to emit light for some time after.
Electromagnetic spectrum
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end.
Blacklight
A blacklight (or often black light), also referred to as a UV-A light, Wood's lamp, or simply ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and not much visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue", which is a contradiction in that they are the type that does "not" look blue.
Violet (color)
Violet is the color at the end of the visible spectrum of light between blue and the invisible ultraviolet. Violet color has a dominant wavelength of approximately 380-450 nanometers. Light with a shorter wavelength than violet but longer than X-rays and gamma rays is called ultraviolet. In the color wheel historically used by painters, it is located between blue and purple. On the screens of computer monitors and television sets, a color which looks similar to violet is made, with the RGB color model, by mixing red and blue light, with the blue twice as bright as the red. This is not true violet, since it is composed of multiple longer wavelengths rather than a single wavelength shorter than that of blue light.
Infrared photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
1_Apprentice
I've never heard that before. Thanks for sharing that information. 
0_Wizard
The eye actually sees blue when you are observing white light anytime the wavelength is  between 450 and 495 nm
The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres.
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Blue
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Light-emitting diode
A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. LEDs are typically small (less than 1 mm) and integrated optical components may be used to shape the radiation pattern. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light.
Color
Color (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color "categories", with names such as red, blue, yellow, green, orange, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc.
Blue
Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colors; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall scattering explains blue eyes.
Abney effect
The Abney effect describes the perceived hue shift that occurs when white light is added to a monochromatic light source. The addition of white light will cause a desaturation of the monochromatic source, as perceived by the human eye. However, a less intuitive effect of the white light addition that is perceived by the human eye is the change in the apparent hue. This hue shift is physiological rather than physical in nature. This variance of hue as a result of the addition of white light was first described by the English chemist and physicist Sir William de Wiveleslie Abney in 1909, although the date is commonly reported as 1910.
Effects of blue light technology
Blue light is a range of the visible light spectrum, defined as having a wavelength between 400−495 nm. This short wavelength means that blue light is a type of high-energy visible light, defined as having a wavelength between 400 and 450 nm. Violet, indigo, and some blue-green light are other types of high-energy visible light. Blue light sources are becoming increasingly common in today’s environment. Exposure to blue light comes from a variety of technologies including computers, smartphones, televisions, and lights. Much of the exposure arises from light emitting diodes (LEDs). Today, many white LEDs are produced by pairing a blue LED with a lower-energy phosphor, thereby creating solid-state light (SSL).
Laser pointer
A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light. Power is restricted in most jurisdictions not to exceed 5 mW. The small width of the beam and low power of typical laser pointers make the beam itself invisible in a reasonably clean atmosphere, only showing a point of light when striking an opaque surface. Some higher-powered laser pointers project a visible beam via scattering from dust particles or water droplets along the beam path.
Interferometry
Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed causing the phenomenon of interference in order to extract information. Interferometry is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, spectroscopy (and its applications to chemistry), quantum mechanics, nuclear and particle physics, plasma physics, remote sensing, biomolecular interactions, surface profiling, microfluidics, mechanical stress/strain measurement, velocimetry, and optometry. Interferometers are widely used in science and industry for the measurement of small displacements, refractive index changes and surface irregularities.