I'm a paper geek and teach paper seaming in one of my drawing classes. I visited the "Pastels in Pieces" exhibition at the Getty solely because it focused on the 18th c. practice of piecing sheets of paper together. The craft developed because artists wanted to make larger pastel paintings or were pasting over mistakes or inserting a sitters head that was rendered separately. These are all techniques my students frequently recoil from trying but this exhibition is a great example of how effective the technique can be. Coypel's bracelet insert is particularly striking.