I think it should be visible from scans, but there are hand made, not computer made. I use pretty much exclusively books and old magazines as source. Usually could be said from 70's to older. Something, that most often could not be said by anybody that he knows where it is taken. None of the material is scanned, but they are photographed from pages, often with slightly altered angles, making optical distortions.
Material is cut/torn/glued/plastered and often hand toned to specific tone. Some pieces are coated with laquer, some remain as they are. They often have this nearly 3D quality compared to what you can sense from small web sample.
