Printing books , magazines , periodicals , catalogs of various organizations , annual reports, etc., has to go through many steps. There is a lot of work to be done in publishing before printing on a printer. Previously, these methods were time consuming , laborious and expensive. But now almost all the work of pre-printing the publication can be done using computers and other hardware and software that can be kept on the desk. It saves time , labor and money and makes the work perfect and clean. Pre-printing using a computer is called desktop publishing or DTP.