At the center of the National Library of Israel Conservation and Restoration Laboratory stands a plain, simple looking metal machine. There are cubes underneath it with some buttons, a small pool of water at the top, and handles in various places. Although inexplicable to the beholder, it turns out that it is a wonderful device called a Leafcaster machine that performs the remarkable task of repairing paper. Its job is to restore the range of items in the Library made from paper where there are holes, tears or missing pieces. The Leafcaster strengthens the paper so that it is preserved by filling it with fresh paper pulp. And this wondrous innovation was first developed for the National Library by the founder of the National Library's Department of Conservation and Restoration, Mrs. Esther Alkalai.
Rather than spending many months repairing damaged paper by hand as undertaken by artisans of old, repair by the Leafcaster is uniform, efficient, and yields the high quality results so critical for precious manuscripts.
Paper is a fibrous material and thus the first step in repairing it using the machine is to create and calculate the precise pulp mixture needed, which requires no small degree of professional training and experience. The pulp can be a mixture of cotton and/or linen fiber and has to be combined so that it is a good color match for the original. Cotton and linen fibers are produced in the lab using a separate machine that grinds them and then combines them to create the pulp. The damaged paper is held down while the water is poured in and the pulp slurry is added to the water. The pulp is pulled to areas where the paper is damaged, filling in the holes, so much so that repair by the Leafcaster strengthens the original material.
The machine used in the laboratory today was built according to Esther Alkalai’s original plans with the addition of some small improvements. Until today, despite the fact that machines now exist that repair paper with the aid of a computer, the Library’s Leafcasting machine achieves the very best results. The trusted metal cubes reveal an amazing machine that rescues and preserves books and manuscripts for the benefit of future generations.