I grew up in a Catholic church, and we called the priests "Father" and then their last name. So "Father Carlin" was *never* "Father John". The rule was sort of relaxed for priests who were not the pastor. Although, my cousin is a priest in Florida, and he is called, "Father Tom" by his parishinors, and he is the pastor of his church. In Catholic churches, there is only one pastor (and you never actually call him "Pastor"), and the other priests assigned to the church are just associates.
You can generally identify a Catholic priest very easily. Priests, even when they are not on official church business, often wear black shirts, pants, and a white collar. If they are a specific order (like Fransiscan), you can identify them from their simple brown robes and rope belt with three knots). If my cousin does anything at all formal or anything at the church, he wears his priest clothes. It's only when he is at home or with family and friends that he is able to dress in civillian clothes, so priests are very easily identifiable. When he celebrates mass, depending on the church season, he wears his black priest clothes with a long white robe and then a colored robe over it. If you've seen pictures of the pope, Catholic priests look kinf of like that when they are celebrating mass with the exception of the hat.
