Air Force blue colours are a variety of colours that are mostly various tones of the colour azure, the purest tones of which are identified as being the colour of the sky on a clear day.
Some air force blue colours, notably the air force blue colour used by the United States Air Force and the colour used by the US Air Force Academy, may look like they are tones of blue instead of azure.[a] However, they are actually dark tones of azure, not blue.[b]
Air Force blue, more specifically Air Force blue (RAF) or RAF blue, is a medium shade of the colourazure. The shade derives from the light blue uniforms issued to the newly formed British Royal Air Force in 1920, which were influential in the design of the uniforms of some other air forces around the world. Similar shades are still used in Royal Air Force uniforms and the Royal Air Force Ensign.
The choice of blue uniforms for the RAF was the result of a surplus of inexpensive medium sky blue coloured herringbonetwill in the United Kingdom, which had been intended for use in the uniforms of Czarist Russian imperial cavalrymen before the Russian Revolution occurred.[1]
The field of the RAF ensign is specified as "NATO stock no.8305-99-130-4578, Pantone 549 C."[2]
Displayed at right is the colour US Air Force Academy blue.
The US Air Force Academy uses a particular shade of azure, subtly different from US Air Force blue, in its sporting and other insignia, described as USAFA blue in official documentation.[4]
^On the RGB colour wheel, which has 12 major colours, blue is the colour at a hue code of 240 degrees and azure is the colour halfway between blue and cyan at a hue code of 210 degrees.
^This is because their hue (h) codes are between 195 and 225, the signature of a tone of azure.[citation needed]