Book - Book Manufacturing in The Modern World

Book Manufacturing in The Modern World

The methods used for the printing and binding of books continued fundamentally unchanged from the 15th century into the early years of the 20th century. While there was of course more mechanization, Gutenberg would have had no difficulty in understanding what was going on if he had visited a book printer in 1900.

Gutenberg's invention was the use of movable metal types, assembled into words, lines, and pages and then printed by letterpress. In letterpress printing ink is spread onto the tops of raised metal type, and is transferred onto a sheet of paper which is pressed against the type. Sheet-fed letterpress printing is still available but tends to be used for collector's books and is now more of an art form than a commercial technique (see Letterpress).

Modern paper books are printed on papers which are designed specifically for the publication of printed books. Traditionally, book papers are off white or low white papers (easier to read), are opaque to minimise the show through of text from one side of the page to the other and are (usually) made to tighter caliper or thickness specifications, particularly for case bound books. Typically, books papers are light weight papers 60 to 90 g/m² and often specified by their caliper/substance ratios (volume basis). For example, a bulky 80 g/m² paper may have a caliper of 120 micrometres (0.12 mm) which would be Volume 15 (120×10/80) whereas a low bulk 80 g/m² may have a caliper of 88 micrometres, giving a volume 11. This volume basis then allows the calculation of a books PPI (printed pages per inch) which is an important factor for the design of book jackets and the binding of the finished book. Different paper qualities are used as book paper depending on type of book: Machine finished coated papers, woodfree uncoated papers, coated fine papers and special fine papers are common paper grades.

Today, the majority of books are printed by offset lithography in which an image of the material to be printed is photographically or digitally transferred to a flexible metal plate where it is developed to exploit the antipathy between grease (the ink) and water. When the plate is mounted on the press, water is spread over it. The developed areas of the plate repel water thus allowing the ink to adhere to only those parts of the plate which are to print. The ink is then offset onto a rubbery blanket (to prevent water from soaking the paper) and then finally to the paper.

When a book is printed the pages are laid out on the plate so that after the printed sheet is folded the pages will be in the correct sequence. Books tend to be manufactured nowadays in a few standard sizes. The sizes of books are usually specified as "trim size": the size of the page after the sheet has been folded and trimmed. Trimming involves cutting approximately 1/8" off top, bottom and fore-edge (the edge opposite to the spine) as part of the binding process to remove the folds so that the pages can be opened. The standard sizes result from sheet sizes (therefore machine sizes) which became popular 200 or 300 years ago, and have come to dominate the industry. The basic standard commercial book sizes in the United States, always expressed as width × height, are: 4¼" × 7" (rack size paperback), 5⅛" × 7⅝" (digest size paperback), 5½" × 8¼", 5½" × 8½", 6⅛" × 9¼", 7" × 10", and 8½" × 11". These "standard" trim sizes will often vary slightly depending on the particular printing presses used, and on the imprecision of the trimming operation. Of course other trim sizes are available, and some publishers favor sizes not listed here which they might nominate as "standard" as well, such as 6" × 9", 8" × 10". In Britain the equivalent standard sizes differ slightly, as well as now being expressed in millimeters, and with height preceding width. Thus the UK equivalent of 6⅛" × 9¼" is 234 × 156 mm. British conventions in this regard prevail throughout the English speaking world, except for USA. The European book manufacturing industry works to a completely different set of standards.

Some books, particularly those with shorter runs (i.e. of which fewer copies are to be made) will be printed on sheet-fed offset presses, but most books are now printed on web presses, which are fed by a continuous roll of paper, and can consequently print more copies in a shorter time. On a sheet-fed press a stack of sheets of paper stands at one end of the press, and each sheet passes through the press individually. The paper will be printed on both sides and delivered, flat, as a stack of paper at the other end of the press. These sheets then have to be folded on another machine which uses bars, rollers and cutters to fold the sheet up into one or more signatures. A signature is a section of a book, usually of 32 pages, but sometimes 16, 48 or even 64 pages. After the signatures are all folded they are gathered: placed in sequence in bins over a circulating belt onto which one signature from each bin is dropped. Thus as the line circulates a complete "book" is collected together in one stack, next to another, and another.

A web press carries out the folding itself, delivering bundles of signatures ready to go into the gathering line. Notice that when the book is being printed it is being printed one (or two) signatures at a time, not one complete book at a time. Thus if there are to be 10,000 copies printed, the press will run 10,000 of the first form (the pages imaged onto the first plate and its back-up plate, representing one or two signatures), then 10,000 of the next form, and so on till all the signatures have been printed. Actually, because there is a known average spoilage rate in each of the steps in the book's progress through the manufacturing system, if 10,000 books are to be made, the printer will print between 10,500 and 11,000 copies so that subsequent spoilage will still allow the delivery of the ordered quantity of books. Sources of spoilage tend to be mainly make-readies.

A make-ready is the preparatory work carried out by the pressmen to get the printing press up to the required quality of impression. Included in make-ready is the time taken to mount the plate onto the machine, clean up any mess from the previous job, and get the press up to speed. The main part of making-ready is however getting the ink/water balance right, and ensuring that the inking is even across the whole width of the paper. This is done by running paper through the press and printing waste pages while adjusting the press to improve quality. Densitometers are used to ensure even inking and consistency from one form to another. As soon as the pressman decides that the printing is correct, all the make-ready sheets will be discarded, and the press will start making books. Similar make readies take place in the folding and binding areas, each involving spoilage of paper.

After the signatures are folded and gathered, they move into the bindery. In the middle of the last century there were still many trade binders – stand-alone binding companies which did no printing, specializing in binding alone. At that time, largely because of the dominance of letterpress printing, the pattern of the industry was for typesetting and printing to take 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 it was almost invariable that 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 the increasing computerization of the process 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. A paperback binding line (a number of pieces of machinery linked by conveyor belts) involves few steps. The gathered signatures, book blocks, will be fed into the line where they will one by one be gripped by plates converging from each side of the book, turned spine up and advanced towards a gluing station. En route the spine of the book block will be ground off leaving a roughened edge to the tightly gripped collection of pages. The grinding leaves fibers which will grip onto the glue which is then spread onto the spine of the book. Covers then meet up with the book blocks, and one cover is dropped onto the glued spine of each book block, and is pressed against the spine by rollers. The book is then carried forward to the trimming station, where a three-knife trimmer will simultaneously cut the top and bottom and the fore-edge of the paperback to leave clear square edges. The books are then packed into cartons, or packed on skids, and shipped.

Binding a hardback is more complicated. Look at a hardback book and you will see the cover overlaps the pages by about 1/8" all round. These overlaps are called squares. The blank piece of paper inside the cover is called the endpaper, or endsheet: it is of somewhat stronger paper than the rest of the book as it is the endpapers that hold the book into the case. The endpapers will be tipped to the first and last signatures before the separate signatures are placed into the bins on the gathering line. Tipping involves spreading some glue along the spine edge of the folded endpaper and pressing the endpaper against the signature. The gathered signatures are then glued along the spine, and the book block is trimmed, like the paperback, but will continue after this to the rounder and backer. The book block together with its endpapers will be gripped from the sides and passed under a roller with presses it from side to side, smashing the spine down and out around the sides so that the entire book takes on a rounded cross section: convex on the spine, concave at the fore-edge, with "ears" projecting on either side of the spine. Then the spine is glued again, a paper liner is stuck to it and headbands and footbands are applied. Next a crash lining (an open weave cloth somewhat like a stronger cheesecloth) is usually applied, overlapping the sides of the spine by an inch or more. Finally the inside of the case, which has been constructed and foil-stamped off-line on a separate machine, is glued on either side (but not on the spine area) and placed over the book block. This entire sandwich is now gripped from the outside and pressed together to form a solid bond between the endpapers and the inside of the case. The crash lining, which is glued to the spine of the pages, but not the spine of the case, is held between the endpapers and the case sides, and in fact provides most of the strength holding the book block into the case. The book will then be jacketed (most often by hand, allowing this stage to be an inspection stage also) before being packed ready for shipment.

The sequence of events can vary slightly, and usually the entire sequence does not occur in one continuous pass through a binding line. What has been described above is unsewn binding, now increasingly common. The signatures of a book can also be held together by Smyth sewing. Needles pass through the spine fold of each signature in succession, from the outside to the center of the fold, sewing the pages of the signature together and each signature to its neighbors. McCain sewing, often used in schoolbook binding, involves drilling holes through the entire book and sewing through all the pages from front to back near the spine edge. Both of these methods mean that the folds in the spine of the book will not be ground off in the binding line. This is true of another technique, notch binding, where gashes about an inch long are made at intervals through the fold in the spine of each signature, parallel to the spine direction. In the binding line glue is forced into these "notches" right to the center of the signature, so that every pair of pages in the signature is bonded to every other one, just as in the Smyth sewn book. The rest of the binding process is similar in all instances. Sewn and notch bound books can be bound as either hardbacks or paperbacks.

Making cases happens off-line and prior to the book's arrival at the binding line. In the most basic case making, two pieces of cardboard are placed onto a glued piece of cloth with a space between them into which is glued a thinner board cut to the width of the spine of the book. The overlapping edges of the cloth (about 5/8" all round) are folded over the boards, and pressed down to adhere. After case making the stack of cases will go to the foil stamping area. Metal dies, photoengraved elsewhere, are mounted in the stamping machine and rolls of foil are positioned to pass between the dies and the case to be stamped. Heat and pressure cause the foil to detach from its backing and adhere to the case. Foils come in various shades of gold and silver and in a variety pigment colors, and by careful setup quite elaborate effects can be achieved by using different rolls of foil on the one book. Cases can also be made from paper which has been printed separately and then protected with clear film lamination. A three-piece case is made similarly but has a different material on the spine and overlapping onto the sides: so it starts out as three pieces of material, one each of a cheaper material for the sides and the different, stronger material for the spine.

Recent developments in book manufacturing include the development of digital printing. Book pages are printed, in much the same way as an office copier works, using toner rather than ink. Each book is printed in one pass, not as separate signatures. Digital printing has permitted the manufacture of much smaller quantities than offset, in part because of the absence of make readies and of spoilage. One might think of a web press as printing quantities over 2000, quantities from 250 to 2000 being printed on sheet-fed presses, and digital presses doing quantities below 250. These numbers are of course only approximate and will vary from supplier to supplier, and from book to book depending on its characteristics. Digital printing has opened up the possibility of print-on-demand, where no books are printed until after an order is received from a customer.