In the RGB color model, used to make colors on computer and TV displays, cyan is created by the combination of green and blue light.
In the RGB color wheel of additive colors, cyan is midway between blue and green.
In the CMYK color model, used in color printing, cyan, magenta and yellow combined make black. In practice, since the inks are not perfect, some black ink is added.
Color printers today use magenta, cyan, and yellow ink to produce the full range of colors.
Cyan and red are complementary colors. They have strong contrast and harmony, and if combined, they make either white, black or grey, depending upon the color system used.
Cyan is the color of shallow water over a sandy beach. The water absorbs the color red from the sunlight, leaving a greenish-blue color.
The dome of the Tilla Kari Mosque in Samarkand, Uzbekistan (1660) is cyan. The color is widely used in architecture in Turkey and Central Asia.
The planet Uranus. seen from the Voyager 2 spacecraft. The cyan color comes from clouds of methane gas in the planet's atmosphere.
A surgical team in Germany. It has been suggested that surgeons and nurses adopted cyan colored gown and operating rooms because it is complementary to the color of red blood and thus reduced glare, though the evidence for this claim is limited.
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)
The web color cyan shown at right is a secondary color in the RGB color model, which uses combinations of red, green and blue light to create all the colors on computer and television displays. In X11 colors, this color is called both cyan and aqua. In the HTML color list, this same color is called aqua.
The web colors are more vivid than the cyan used in the CMYK color system, and the web colors cannot be accurately reproduced on a printed page. To reproduce the web color cyan in inks, it is necessary to add some white ink to the printer's cyan below, so when it is reproduced in printing, it is not a primary subtractive color. It is called aqua (a name in use since 1598) because it is a color commonly associated with water, such as the appearance of the water at a tropical beach.
While both the additive secondary and the subtractive primary are called cyan, they can be substantially different from one another. Cyan printing ink can be more saturated or less saturated than the RGB secondary cyan, depending on what RGB color space and ink are considered.
Process cyan is not an RGB color, and there is no fixed conversion from CMYK primaries to RGB. Different formulations are used for printer's ink, so there can be variations in the printed color that is pure cyan ink. This is because real-world subtractive (unlike additive) color mixing does not consistently produce the same result when mixing apparently identical colors, since the specific frequencies filtered out to produce that color affect how it interacts with other colors. Phthalocyanine blue is one such commonly used pigment. A typical formulation of process cyan is shown in the color box at right.
In science and nature
Color of water
Pure water is nearly colorless. However, it does absorb slightly more red light than blue, giving large volumes of water a bluish tint; increased scattering of blue light due to fine particles in the water shifts the blue color toward green, for a typically cyan net color.
Cinecolor, a bi-pack color process, the photographer would load a standard camera with two films, one orthochromatic, dyed red, and a panchromatic strip behind it. Color light would expose the cyan record on the ortho stock, which also acted as a filter, exposing only red light to the panchromatic film stock.
Cyanosis is an abnormal blueness of the skin, usually a sign of poor oxygen intake. i.e. the patient is "cyanotic".