Royal blue. Royal blue describes both a bright shade and a dark shade of azure blue. It is said to have been invented by millers in Rode, Somerset, a consortium of which won a competition to make a dress for the British queen, Charlotte of Mecklenburg-Strelitz. Traditionally, dictionaries define royal blue as a deep to dark blue, often with a purple or faint reddish tinge. By the 1950s, many people began to think of royal blue as a brighter color, and it is this brighter color that was chosen as the web color royal blue. The World Wide Web Consortium designated the keyword royalblue to be this much brighter color, rather than the traditional darker version of royal blue.