So I am in a few facebook groups where we all make book art. Everyone's photos are taken with a phone (I'm assuming) ,have Moire, a bit of distortion to the pages, and that strange black coloring that never disappears, just moves around, no matter the angle. That's why I was trying to steer away from mobile pics, and see if I got better results with a better camera.
I got a new tripod and a level for these set of pictures (although I still can't tell if I am using it correctly. do these look better?). I can't retake pictures of past books because I've already had to deliver them to the customer, so each set of advice you give me, I start on my new completed book.
This one is a different type of fold, so the moire isn't as bad, but the dreaded black line is always there. I took hundreds of pictures and still couldn't get rid of it, even with extra light.
I also used a good trusty protractor to get my angle better, like you suggested and placed a book under the backdrop to prop it up a bit. That actually made the most difference with the lighting. (the last one is without the book underneath.)
Most of these were taken f/8, iso400-800, 1/250