I take macro photos of small jewelry items, mostly for internet catalogs. Now, one of my clients wants photos for a printed catalog. Every item has to be printed in actual size. Let's say it's a coin. So if you place a real coin onto its printed image they have to match exactly. I am confused. How do I know what size of a on-screen picture matches a printed image. I feel like there should be a simple answer to this. Could someone show me how it is done, please?