I think you may be talking about the 1989 adaptation of Hard to be a God. I have been unable to find a good summary of the 1989 adaptation, but the Wikipedia article for the 2013 remake covers the high points and the book site I linked above mentions the printing press.
A group of 30 scientists travel from Earth to a nearly-identical alien planet that is culturally and technologically centuries behind. The inhabitants of this planet have brutally suppressed a renaissance movement, murdering anybody they consider to be an intellectual, and thus the planet is stuck in the middle ages. Anton, one of the scientists from Earth, is sent to infiltrate the local populace of the Kingdom of Arkanar and help them progress as a society, although he is forbidden from getting involved with local politics or forcibly interfering with the advancement of technology or culture. He assumes the identity of Don Rumata, a nobleman who resides in a large castle surrounded by poverty. There, he lives with Ari, a young woman whom he has taken as his bride, and the juvenile prince of Arkanar. Rumata's presence divides local opinion; some treat him as a God, others despise him.
Found via search terms of film medieval planet torture printing press (not my first set of search terms, admittedly)