@John, the Bleau Atlases were chosen as part of a multi-year condition survey we are conducting in the RBMS collections. We use three main criteria when deciding priorities: value, use and risk. With the data we collected so far, and in conjunction with the Head of Collection Development, we chose to bring these to the lab. You are correct that these are beautifully printed on very fine paper. The fold outs, however, have been mis-folded several times, making them vulnerable to tearing and loss (and very wrinkled as they now have several folds rather than one, which can lead to further damage). Each volume needed dry cleaning and multiple minor page mends.The vellum-over-boards bindings are quite vulnerable to fluctuations in environmental conditions. We have constructed custom enclosures for each volume to keep the boards from warping.There is a lot of need in our collections as you know. Our surveys, knowledge of the materials, and close working relationships with RBMS librarians and staff help us identify items for conservation.Beth Doyle, Collections Conservator