Navy Blue (#000080) is a very dark, highly saturated blue hue. Navy is named after the uniforms of the British Royal Navy and is the most popular dark colour for corporate brands.
In RGB it is made of 0 red, 0 green and 128 blue. Its HSL hue angle is 240° with 100% saturation and 25% lightness, while its perceptual OKLCH lightness is 27% with a chroma of 0.188. For print, a starting CMYK mix is 100% cyan, 100% magenta, 0% yellow and 50% black.
As a text color on white, Navy Blue has a contrast ratio of 16.01:1, which passes WCAG AA for normal text. On black it reaches 1.31:1 and fails AA. If you use Navy Blue as a background, put white text on it. The APCA lightness contrast is Lc 0 for black text and Lc -104 for white text.
Its perceptual complement is #332400, close to gunmetal. Colors that look most similar are ultramarine, midnight blue, indigo. It looks fairly similar to people with red-green color blindness (ΔE 3), so its meaning mostly survives.