It's an English language film made in the 60's or early 70's. I saw it around 1978. The only scene I recall in it is where 3 characters are in a bedroom with a large mirror attached to a dresser. The male character looks in the mirror and maybe realizes that one of the 2 females in the room is a witch/demon or something evil basically. I think it's during this scene that the movie goes from B/W to full color. I recall at the time checking the TV guide for the name of the movie and I thought it was Black Sunday or Black Sabbath, but I've seen those and they don't seem to be what I remember seeing. This was one of those rare movies that freaked me out and it has stayed with me ever since. But I fear I might be mis-remembering it.