If you wanted to produce a manuscript or submission in something like book form for limited distribution, you would most likely print out the pages consecutively, possibly double-sided, and bind them in some fashion. But that is not how books are printed. Several pages are printed on a single sheet of paper, called a "signature", and when you look at it, they do not appear to be in order. It is then folded in a complex fashion, after which the folded signatures are placed in order and glued together at one edge. The other three edges are then cut, allowing the book to be opened.
All this is easiest to see in a large, unbound publication ie a newspaper. From a simple glance it should be obvious that the first and last page are printed on a single sheet of paper, with the second and second last on the reverse: four pages in all. If you were to fold the sheet in two, you would turn it into eight pages. Fold it again, and you would have sixteen. Depending on the size of the page and the size of the sheet, it is possible to place 64 pages on one signature: 32 per side. However, signatures of eight or sixteen pages are most common.
The pages are printed in such a manner that they will come out in the correct order once they are folded. If a photograph or diagram has to span two pages, as is common in the National Geographic, then they must line up to a fraction of a millimetre. That is why girlie magazines place their double-page spread as a centrefold; it is much easier to print.
Before a book is produced, the publishers must do a cost analysis of the number of copies to be printed, and the total cost. You can easily conclude, therefore, that one of the major issues under consideration will be the size of the signature, and this will impact on such things as the font size, the width of margins, whether new chapters will commence on a separate page, and the size of diagrams in the middle of pages. It also explains the frequent presence of blank pages at the end of books.
In all but the most tightly bound books, the signatures can be recognized as creases along the edges when the book is closed, but they are most clearly visible in loosely bound items, such as notebooks. If page-sized photographs are included, they will nearly always be squeezed in between two signatures. Before the advent of computerised printing, books were compiled by hand. That is why, in older books, you will frequently find a mysterious number or letter at the bottom of some pages. They used to puzzle me, but their purpose is straightforward: they mark the start of each signature, so that the human compiler will know in what order to pack them.
Now that I have acquired this information, looking at books has never been the same. But there are a few other matters, unrelated to printing, which you might find interesting. In older books the pages will often be disfigured with brown discolourations. These are due to the acid in the paper, which is made from wood pulp. They do not appear in books a couple of hundred years old, when paper was made from rags, so very old books tend to be in better condition that more recent ones. On the other hand, glossy paper is manufactured by adding clay to the mixture. And the finest type of paper is known as Bible paper. The reason should be obvious, once you think of it. The average Bible has as many pages as War and Peace, but many of them are quite compact. Also, if a Bible is read at all, it is read over and over again. Thus, the paper must be especially thin and especially strong.
All this is easiest to see in a large, unbound publication ie a newspaper. From a simple glance it should be obvious that the first and last page are printed on a single sheet of paper, with the second and second last on the reverse: four pages in all. If you were to fold the sheet in two, you would turn it into eight pages. Fold it again, and you would have sixteen. Depending on the size of the page and the size of the sheet, it is possible to place 64 pages on one signature: 32 per side. However, signatures of eight or sixteen pages are most common.
The pages are printed in such a manner that they will come out in the correct order once they are folded. If a photograph or diagram has to span two pages, as is common in the National Geographic, then they must line up to a fraction of a millimetre. That is why girlie magazines place their double-page spread as a centrefold; it is much easier to print.
Before a book is produced, the publishers must do a cost analysis of the number of copies to be printed, and the total cost. You can easily conclude, therefore, that one of the major issues under consideration will be the size of the signature, and this will impact on such things as the font size, the width of margins, whether new chapters will commence on a separate page, and the size of diagrams in the middle of pages. It also explains the frequent presence of blank pages at the end of books.
In all but the most tightly bound books, the signatures can be recognized as creases along the edges when the book is closed, but they are most clearly visible in loosely bound items, such as notebooks. If page-sized photographs are included, they will nearly always be squeezed in between two signatures. Before the advent of computerised printing, books were compiled by hand. That is why, in older books, you will frequently find a mysterious number or letter at the bottom of some pages. They used to puzzle me, but their purpose is straightforward: they mark the start of each signature, so that the human compiler will know in what order to pack them.
Now that I have acquired this information, looking at books has never been the same. But there are a few other matters, unrelated to printing, which you might find interesting. In older books the pages will often be disfigured with brown discolourations. These are due to the acid in the paper, which is made from wood pulp. They do not appear in books a couple of hundred years old, when paper was made from rags, so very old books tend to be in better condition that more recent ones. On the other hand, glossy paper is manufactured by adding clay to the mixture. And the finest type of paper is known as Bible paper. The reason should be obvious, once you think of it. The average Bible has as many pages as War and Peace, but many of them are quite compact. Also, if a Bible is read at all, it is read over and over again. Thus, the paper must be especially thin and especially strong.
