The term blue may refer to any of a number of similar coloursColor (or colour, see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, white, etc. Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties ...colours. The sensationIn psychology, sensation is the first stage in the biochemical and neurologic events that begins with the impinging of a stimulus upon the receptor cells of a sensory organ, which then leads to perception, the mental state that is reflected in statements like "I see a uniformly blue wall." A sensation that might lead to that statement could include the excitation of cone cells in the retina, spatially varying in the proportion of "blue" and "green" cone excitation due to portions of the wall receiving different proportions of yellowish artificial ...sensation of blue is evoked by light having a spectrum dominated by energy in the wavelengthIn physics, wavelength is the distance between repeating units of a propagating wave of a given frequency. It is commonly designated by the Greek letter lambda (λ). Examples of wave-like phenonomena are light, water waves, and sound waves. In a wave, a property varies with the position. For example, this property can be the air pressure for a sound wave, or the magnitude of the electric or the magnetic field for light. The ...wavelength range of about 440–490 nmA nanometre (American spelling: nanometer, symbol nm) (Greek: νάνος, nanos, dwarf; μετρώ, metrό, count) is a unit of length in the metric system, equal to one billionth of a metre, which is the current SI base unit of length. It can be written in scientific notations as 1×10−9 m (engineering notation) or (exponential notation) — both ...nm.

Blue is considered to be one of the three primary additive colours in the RGBThe RGB color model is an additive model in which red, green, and blue (often used in additive light models) are combined in various ways to reproduce other colors. The name of the model and the abbreviation ‘RGB’ come from the three primary colors, red, green, and blue and the technological development ...RGB system; blue lightLight is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, the word is sometimes used to mean electromagnetic radiation of all wavelengths. The elementary particle that defines light is the photon. The three basic properties of light (i.e., all electromagnetic radiation) are: * Intensity, or alternatively amplitude, which is related to the perception of brightness ...light has the shortest wavelengthIn physics, wavelength is the distance between repeating units of a propagating wave of a given frequency. It is commonly designated by the Greek letter lambda (λ). Examples of wave-like phenonomena are light, water waves, and sound waves. In a wave, a property varies with the position. For example, this property can be the air pressure for a sound wave, or the magnitude of the electric or the magnetic field for light. The ...wavelength range of the three additive primary coloursPrimary colors, for humans, are sets of three colors that can be combined to make a whole gamut of colors. For additive combination of colors, as in overlapping projected lights or in CRT displays, the primary colors normally used are red, green, and blue. For subtractive combination of colors, as in mixing of pigments or dyes, such as in printing, the primaries normally used are magenta, cyan, and yellow. These choices of primary colors are not ...additive primary colours. The English language commonly uses "blue" to refer to any colour from navy blueNavy blue is an especially dark shade of the color blue. Some people mistake navy blue for black, especially when concerning clothing, most notably the navy blue pinstripes of the New York Yankees home uniform. Navy blue got its name from the dark blue (contrasted with white) worn by officers in the Royal Navy since 1748 and subsequently adopted by other navies around the world. In the US Navy and the Canadian Navy, many uniforms which are called "blue" (e.g. Working Blues and Service Dress Blues) Canada (uniforms 1, 1A, 2B, 3, 3A, 3B (winter), ...navy blue to cyanCyan (from Greek κυανός, meaning "blue") may be used as the name of any of a number of a range of colors in the blue/green part 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 removal of red from white light. As such, cyan is the complement of red: cyan pigments absorb red light. Cyan is also called aqua or ...cyan.

The complementary colourComplementary colors are pairs of colors that are in some way opposites of each other. These pairs are different between color science, and art and the printing process.complementary colour of blue in colour scienceColor (or colour, see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, white, etc. Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories ...colour science is yellowYellow is the color evoked by light that stimulates both the L and M (long- and medium-wavelength) cone cells of the retina about equally, but does not significantly stimulate the S (short-wavelength) cone cells; that is, light with lots of red and green but not much blue. Light with a wavelength of 570–580 nm is a yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths. Yellow's colorimetrically defined complementary ...yellow (on the HSV colour wheelThe HSV (Hue, Saturation, Value) model, also known as HSB (Hue, Saturation, Brightness), defines a color space in terms of three constituent components: * Hue, the color type (such as red, blue, or yellow): ** Ranges from 0–360 in most applications. Each value corresponds to one color. Examples: 0 is red, 45 is a shade of orange and 55 is a shade of yellow. * Saturation, the intensity of the color: ** Ranges from 0–100%. 0 means no color, i.e., a shade of grey between black and white. 100 means intense color. ** Also sometimes ...HSV colour wheel), while in artArt is a (product of) human activity, made with the intention of stimulating the human senses as well as the human mind; thus art is an action, an object, or a collection of actions and objects created with the intention of transmitting emotions and/or ...art the complementary colour to blue is considered to be orangeThe colour orange occurs between red and yellow in the visible spectrum at a wavelength of about 585–620 nm, and has a hue of 30° in HSV colour space. The complementary colour of orange is azure, a slightly greenish blue. With pigments such as paints or inks, a mixture of the subtractive primary colours in the proportion of 75% yellow and 25% magenta produce the secondary colour orange. Orange pigments are largely in the ochre or cadmium families, and ...orange (based on the Munsell colour wheelIn colorimetry, the Munsell color system is a color space that specifies colors based on three color dimensions, hue, value (or lightness), and chroma (roughly saturation). It was created by Professor Albert H. Munsell in the first decade of the 20th century. Several earlier color order systems had placed colors into a three dimensional color solid of one form or another, but Munsell was ...Munsell colour wheel).