What does sky blue mean? What does sky blue stand for?

Blue is a color, one of the three primary colors of red, green and blue. Among the three primary colors, its wavelength is the shortest (about 470 nm). Because sunlight is Rayleigh scattered by dust in the air, the clear sky is blue. Due to the absorption of light of about 750 nanometers by hydrogen-oxygen bonds in water molecules, a large amount of water is concentrated into blue. Interestingly, heavy water is colorless because deuterium-oxygen bonds absorb light with a relatively long wavelength (about 950 nm). The complementary color of blue is orange. Types of blue: ultramarine, sky blue, cobalt blue, lake blue, indigo, azure, sapphire blue, purple blue, indigo, skylark blue, sky blue, dark blue, light blue, tile blue, blue black, etc. Usage and symbolism Blue is the symbol of eternity and the coldest color. Pure blue shows a kind of beauty, gentleness, reason, tranquility and cleanliness. Blue has a rational and accurate image because of its calm characteristics. In commercial design, most commodities or corporate images that emphasize technology and efficiency choose blue as the standard color and corporate color, such as computers, cars, photocopiers and photographic equipment. In addition, blue also represents melancholy, which is influenced by western culture. This image is also used in literary works or commercial designs with emotional appeals. In many countries, police uniforms are blue. Police and ambulance lights are usually blue. Because blue means courage. Many air force and navy uniforms are blue. Generally, the air force is sky blue and the navy is dark blue. Blue-collar workers generally refer to manual workers in factories. The name comes from the blue overalls that workers usually wear to work. In contrast, white-collar workers generally refer to office workers and generally wear white shirts. In Islam, blue is a pure color. European aristocrats are usually called "aristocrats". Some people think the name comes from their pale skin. In the west, blue is generally the color of boys, and pink is generally used by girls. Boys' clothes, toys, strollers, etc. Usually light blue. Interestingly, this habit only started after the First World War. Before that, blue was the color of girls and pink was the color of boys. So gay men used to be called "blue" in the west. The Blue Sox Club refers to a private gathering of cultural circles at that time. Because the vast majority of people attending such parties are women, and women at that time could not enter the university. The word "blue socks" quickly targeted at women, so it was given a discriminatory meaning. In Britain, the wedding custom requires each bride's dowry as follows: "some old, some new, some borrowed, some blue." Some old, some new, some borrowed, some blue loyalty. ) Blue hour is blue time, which is very popular in America and Britain. It refers to the time after work, that is, the time to relax. Blue also means beauty, freshness, tranquility and melancholy! Politics The Pan-Blue Alliance of Taiwan Province Province is a political group. In the United States, blue is generally the color of the American Democratic Party. In Britain and Canada, blue is the color of the Conservative Party. Blue books are usually yearbooks or similar reference books. From 1860, ships crossing the Atlantic at the highest speed were awarded the title of blue shirt. Blue ribbons are usually used to mark high-quality things. The color of Oxford University is dark blue, and that of Cambridge University is light blue. In the west, subcutaneous congestion caused by internal injuries is often called blue block. In China, people call this kind of congestion Qing Wu Tuo. Generally, veins are painted blue in medical schematic, but in fact, venous blood is purple. Microsoft's Windows system will display blue screen of death when there is an irreparable error. In the American Civil War, the military uniform in the north was blue, so blue was often used to represent the north, and the military uniform in the south was gray, so gray was often used to represent the south. IBM's nickname is "Blue Giant". The first computer made by the company to beat Garry Kasparov, the world chess champion, was called Deep Blue. In English-speaking countries, if there are two full moons in a month, this phenomenon is called "blue moon". Blue is considered as the cooler color. Music blue is a name often used in the music industry. Many bands and songs are named in blue. In addition, an American music is called blues. Color code network code = #0000FF RGB red green blue system = (red 0, green 0, blue 255) CMYK four-color printing system = (cyan C 100, magenta M 100, yellow Y0, black K0) HSV system = (primary color 240, saturation/kloc-0.