The color "blue" is symbolic of many things, yet the most curious may be matters of obscenity and puritanical decree. The term "Blue laws" dates back to 1781 when the Reverend Samuel Peters published his history of Connecticut. He painted the strict laws of the puritan colonists as "blue laws," or laws that were enforced by brutality. "Blue laws" became shorthand for any strict, old-fashioned laws, such as laws forbidding liquor sales on Sundays. The use of the word "blue" to refer to risqué content was first recorded in Scotland in 1824. the Scottish Gallovidian Encyclopedia linked "blue" with a "smutty touch in song-singing, chatting, or piece of writing." One theory as to why "blue" meant "lewd" is that prostitutes in prison may have been dressed in blue gowns. Another theory mentions a series of ribald French books titled Bibliotéque Blue. Both of these things could have influenced the term "blue movies." Pornography has been outlawed at various times and places, so blue laws might have forbidden the movies and thus the color became associated with the content. Also, when you curse a blue streak, you're talking dirty, and such language can be connected to explicit films. Another explanation for "blue movies" is that striptease acts may have once used blue spotlights. Hope this helps.