I'm about to start a large format project on cemetery headstones. The project will compare 18th century engravings carved into the stone with 21st century laser printed images of the deceased.

While I'm confident that I can make photos of the 18th century headstones without any legal restrictions, I'm wondering about 21st century privacy issues when it comes to photographing a modern headstone that contains a person's likeness embedded in the stone. I'm also wondering if I'm possibly violating a copyright by reproducing a likeness without express written permission from the family of the deceased.

Any thoughts or legal opinions?