why x rated film call blue film?

During the olden days, many states established what is commonly known as, "Blue laws." It was done to encourage people to go to church and pray as much as possible. Some states still follow some traces of these laws even today. For example, in Connecticut you still can NOT purchase alcohol after 8PM during week days, and at anytime on Sundays. In the olden days, even the sale of "non-essential" items such as soap powders, or household cleaners were banned on Sunday because Sunday was the day to go to Church and not for sitting around the house, getting drunk or cleaning your kitchen floor.

Over the years, thus, everything which was considered "Banned" came under what is commonly known as the, "BLUE law."

Pornography, certainly would fall under this category and obviously X-rated movies were thus referred to as, "Blue Movies." Of course in those days there was no such thing as a rating system. So certainly "X" had no meaning yet.

One other possibility for the use of the word "Blue" dates back to the days of burlesque. It was quite customary for the performers to carry out their act under Blue spotlights. These clubs were commonly known as Blue Clubs for this reason.

Not blue Films. Blue Movies..

I used to know why this was, I think it might have something to do with all the guys in the theater smoking and it being hazy and foggy, but I doubt that was it.

because when guys watch them they get blue balls

coz. it shouldn't be posted in the math section

Dunno, but just to note that not all x-rated films are "blue movies" - the x-rating might be e.g. for violence.

I don´t know, here they are called green...

Anabel