It may be just that you used low resolution 300 should be fine or maybe the photos were printed so that they may not be copied. They look like a moire` pattern to me. Which could be a copy protection process. I would try to contact the author and beg copies of the pictures. We are often generous with a distant relitive when it comes to artifacts that relete to mutual ancestors.

http://en.wikipedia.org/wiki/Moir%C3%A9_pattern