Letterpress can produce work of high quality at high speed, but it requires much time to adjust the press for varying thicknesses of type, engravings, and plates called makeready. The process requires a high degree of craftsmanship, but in the right hands, letterpress excels at fine typography. It is used by many small presses that produce fine, handmade, limited-edition books, artists' books, and high-end ephemera such as greeting cards and broadsides. Because of the time needed to make letterpress plates and to prepare the press, setting type by hand has become less common with the invention of the photopolymer plate, a photosensitive plastic sheet that can be mounted on metal to bring it up to type high.