After the signatures are folded and gathered, they move into the bindery. In the middle of last century there were still many trade binders – stand-alone binding companies which did no printing, specializing in binding alone. At that time, because of the dominance of letterpress printing, typesetting and printing took place in one location, and binding in a different factory. When type was all metal, a typical book's worth of type would be bulky, fragile and heavy. The less it was moved in this condition the better: so printing would be carried out in the same location as the typesetting. Printed sheets on the other hand could easily be moved. Now, because of increasing computerization of preparing a book for the printer, the typesetting part of the job has flowed upstream, where it is done either by separately contracting companies working for the publisher, by the publishers themselves, or even by the authors. Mergers in the book manufacturing industry mean that it is now unusual to find a bindery which is not also involved in book printing (and vice versa).If the book is a hardback its path through the bindery will involve more points of activity than if it is a paperback. Unsewn binding, is now increasingly common. The signatures of a book can also be held together by "Smyth sewing" using needles, "McCain sewing", using drilled holes often used in schoolbook binding, or "notch binding", where gashes about an inch long are made at intervals through the fold in the spine of each signature. The rest of the binding process is similar in all instances. Sewn and notch bound books can be bound as either hardbacks or paperbacks.