Agate burnishers are used to smooth out genuine gold leaf (any metal leaf) after it has been adhered to a surface through water gilding, giving the gilded surface an attention-grabbing luster. The process of bookbinding requires many raw materials such as paper, threads, tape, boards and fabric. All these items are available in the market in different quality levels and grades. Perfect binding involves collating all the pages or signatures of a book, roughening and flattening the edge of the spine area, and then applying a flexible adhesive and attaching a paper cover to the spine. Paperback novels are one example of perfect binding.