Sky blue


Sky blue refers to a collection of shades comparable to that of a clear daytime sky. Typically it is a shade of cyan or light teal, though some iterations are closer to light azure or light blue. The term is attested from 1681.
Displayed at right is the web colour.

Variations

Celeste

Celeste is the colloquial name for the pale turquoise blue colour. The same word, meaning "of the sky", is used in Spanish, Portuguese and Italian for the colour. Etymologically, it is derived by Latin term caelestis, that means del cielo in Italian. There are two "conventional" colours denominated celeste, according to the colour models. One is the pure Celeste, ' which may be referred as the "true" celeste as it is traditionally or officially understood; in English, it may also be referred to as Italian sky blue and Bianchi Green, referring to Bianchi, the famous Italian company for bikes, the first in the history of vehicles, whose colour is characteristic. The Japanese equivalent is known as sora iro or mizuiro, referring to the colour of the sky or its reflection on the sea. The other one is also another conventional celeste containing 100% of blue, associated to a more generic colour of the sky and remembering a type of light zenithal blue and the next sky blue gradations.
File:Celeste puro tra sole e orizzonte a Torregrotta.jpg|thumb|Pure Celeste between Spadafora and Torregrotta, Sicily in September; the colour of the ideal sky is shown with a perfect or near-perfect weather, especially close to the horizon, where the cyan is more evident.
Celeste, that is, the pure Celeste strictly speaking from here on, is a gradation of the cyan and a cold colour. It is the colour of the sky with optimal visibility, when it is clear, perfectly or near-perfectly cloudless and sunny with an optimal quantity of humidity, absence or optimal quantity of atmospheric dust, aerosol/particulates with a good or at least moderate AIQ, absence of mist, haze, resulting in a good diffusion of light blue without saturation, which causes the prevalence of the white or of the warm colours of sunrise and sunset; in these excellent conditions, it is possible to see Celeste and its variations perpendicularly to the Sun, toward the horizon, where the sunlight is maximum as the sky is directly illuminated, and these shades merge with the golden light of solar rays and the white of the horizon, both in the morning and afternoon, or even across the entire region between the star and the horizon, when the star is high, relatively next to solar or true noon. In particular, in the warm seasons, with the inclination of a hemisphere with respect to the Sun, there are simultaneously the optimisation of sunlight, daylight hours, and so the pure celeste might be visible in the entire region between the horizon and Sun both in the morning and afternoon; generally, the higher the Sun is during the day and the year, the less visible celeste and variations will be. In particular, they are most visible in the morning across the Sun and the horizon in the early hours with the rising of the star, sometimes even until noon, until they are reduced to a few stripes on the horizon, where the cyan is more intense. In the afternoon, it is the opposite and the pure celeste and similar gradations could be widely visible between the Sun and horizon when the star is high, but starting to go down, that is especially in the early afternoon hours. Instead, in the cold season, with a low Sun and sunlight, the pure celeste may be visible only at the horizon, where the cyan is more intense for the maximum light, but is more difficult to see because of the major weather instability. Since sunlight is strongest at the horizon, that is where the pure celeste is more evident, producing the tonalities of the cyan, very close to the white.
File:Celeste puro tra sole e orizzonte.jpg|thumb|Pure Celeste between Spadafora and Torregrotta, Sicily, with perfectly clear, serene and sunny weather in September. The pure celeste is more evident close to the horizon, where the cyan is more intense.
Alternatively, other variants, like Celeste polvere, ''Pallido and Velato, are visible towards the horizon when the Sun is near to the zenith, always with conditions for good visibility. In the afternoon, always with good conditions, these three types of celeste, together with softer and less bright shades of celeste, are visible at a straight angle from north to south, until around sunset.
In reality, it can be difficult to observe the pure celeste, being the colour of a clear day with optimal meteorological conditions; other shades of blue are often visible in the sky, as Light Sky Blue and similar gradations, among which is the other conventional celeste, similar to the light blue sky colours rather than the pure celeste. One scientific explanation needs to be made: the Sun emits light across the entire electromagnetic spectrum and so celeste, which is very close to the white with a RGB of 178,255,255, is very luminous, and so visible in the direction of the Sun because it is there the maximum quantity of solar light is present, especially towards the horizon, even if human eyes can only perceive the visible light. Here celeste and variations are more visible in the warm seasons because of the inclination of a hemisphere with respect to the Sun, in spring and especially summer, with the optimisation of solar light, hours of daylight and meteorological factors.
Being the gradation of near-perfectly sunny and clear sky, the colour of an ideal sky, it is difficult to see pure celeste, especially during the coldest or most unstable seasons; instead, generically the sky shows the colour of the other conventional celeste with 100% of blue, recalling a light zenithal blue and the next other types of sky blue; this is not surprising due to the best diffusion of the blue because of the Raylegh scattering.
Bleu celeste is a rarely occurring tincture in heraldry. This tincture is sometimes also called ciel or simply celeste'. It is depicted in a lighter shade than the range of shades of the more traditional tincture azure, which is the standard blue used in heraldry.

Gradations

The Italian Wikipedia cites Il dizionario dei colori: nomi e valori in quadricromia by S.Fantetti and C.Petracchi and describes multiple variants of celeste as shown below, plus details as defined in the infobox above.
colournameCMYKRGBHEX
celeste 030000000000178255255B2FFFF
celeste polvere powdery010000000000230255255E6FFFF
celeste pallido 016000003000204255255CCFFFF
celeste velato Veiler overcast020010010000204230230CCE6E6
celeste opaco opaque05002002000012820420480CCCC

Light sky blue

Displayed at right is the web colour light sky blue. It is close in shade to baby blue.

Medium sky blue

Displayed at right is the colour medium sky blue. This is the colour that is called sky blue in Crayola crayons. This colour was formulated by Crayola in 1958.
"Sky blue" appears in the 32, 48, 64, 96 and 120 packs of crayons.

Vivid sky blue

Displayed at right is the colour vivid sky blue.

Deep sky blue

Deep sky blue is an azure-cyan colour associated with deep shade of sky blue.
Deep sky blue is a web colour.
This is the colour on the colour wheel halfway between azure and cyan.
The colour name deep sky blue came into use with the formulisation of the X11 colour names over 1985–1989.
The normalised colour coordinates for deep sky blue are identical to Capri, which first came into use as a colour name in English in 1920.
File:Blue Grotto, Capri, Italy.jpg|alt=Sky-blue waters of the Blue Grotto in Capri|thumb|Deep sky blue waters of the Blue Grotto in Capri, namesake of the original name for this colour

French sky blue

At right is displayed the colour French sky blue, which is the tone of sky blue that is called sky blue in the Pourpre.com colour list, a colour list widely popular in France.

Spanish sky blue

Spanish sky blue is the colour that is called celeste in the Guía de coloraciones by Rosa Gallego and Juan Carlos Sanz, a colour dictionary published in 2005 that is widely popular in the Hispanophone realm.

Dark sky blue

Displayed at right is the colour dark sky blue.
This is the colour called sky blue in Pantone.
The source of this colour is the "Pantone Textile Paper eXtended " colour list, colour #14-4318 TPX—Sky Blue.

In culture

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