The Watermark Identification in Rembrandt's Etchings project (WIRE), a multidisciplinary collaboration among museums, university faculty, and students, aims to promote digital access to Rembrandt paper scholarship. Its chief innovation is the use of the decision tree model for the visual differentiation of watermarks, incorporated into an interactive and expandable online identification aid illustrated with images of all known examples. New image data provided by the Watermark Imaging Box Project (WImBo) will significantly enhance the decision tree through images of greater clarity and completeness. WIRE has also begun to discover new watermarks on Rembrandt's papers; increased availability of full-sheet images of prints and drawings from Rembrandt and his circle from as yet untapped collections will drive construction of a watermarks database, and also assist efforts to date papers without watermarks.