Karman may be a form of a sur-name I have been researching that our family has traced back to Khel, Germany just outside of the present Strassbourg. Our family came to America in the mid-1700's but there have been individuals who remained in Germany with the same last name who might have come even a century or two later. Other spellings include Kirmann, Kirrman, Kirrmann, Carman and numerous variations. In the 1700's the family was decidedly Lutheran. You might try Lutheran records, assuming that the family would have remained protestant.