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We’re almost there now. Binding the printed matter into a book, magazine or other product is the final step in the production process. And it is only really at this stage that the printed product is given its final appearance – so it is an important stage.
However, before discussing the various binding, folding and scoring techniques, we need to go back a few steps. Before the sheet is printed, imposition is carried out. This entails organising the pages so that they end up in the right order. The number of pages that fit on each sheet varies depending on the size of the printing press and the format of the printed matter. In some cases only 4pages might fit, in others 8, 16 or 32. The pages then have to be combined in the right order to form a printed product. |
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To ensure that the pages of a document appear in the right order, it is essential that they are folded in the right way. Folding is almost always done mechanically, but it is important to check that the fold runs parallel to the fibre direction. When a sheet is folded in more than one direction – this is called cross-folding – the fold that runs along the spine of the product must also run parallel to the fibre direction. If the fold goes against the fibre direction there is a high risk of cracking at the fold. It also makes the fold uneven.
Occasionally, the paper is so thick that it can be difficult to fold it without causing cracks and unevenness. To avoid this the paper is scored before folding, which basically involves pressing a channel into the paper where the fold is to run. It is especially important to score paper where images or tint plates run across the fold, as cracks are more noticeable in tints and images. For printing processes which involve drying the paper, such as in digital presses, even low thicknesses and grammages should be scored before folding.
When producing books, it is also important to ensure that the fibre direction runs along the spine so that the book opens nice and easily. If this is not done, the pages can expand and the book will not close properly – which is certainly not the desired effect. |
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Die cutting is a common method of enhancing the appearance, feel and message of a printed product. Die cutting involves using a die forme to press a pattern out of the paper such as a round window on the cover that reveals parts of what is on the first page. This can also be used for indexing folders, for instance. |
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The final phase in putting together paper to form a book or other printed product is called binding. Binding encompasses a wide range of methods, each with its own particular conditions. Here we will be covering some of the most common methods.
– Wire-stitching – also called stapling – is the most common and in fact the cheapest binding technique, and is used primarily in the production of brochures and other simple printed matter. Apart from being cheap, the advantage of the method is that it is fast and easily manageable, and is suitable for all grades of paper. As the name implies, the product is bound by passing one or more metal wires or staples through the pages and covers, just like stapling together office documents. The two most common methods are spine stitching and flat stitching. In spine stitching, the staples are driven through the folds on folded sheets, whereas in flat stitching they go through the outer edge of flat sheets.
– Perfect binding – or adhesive binding – is a common binding method in products of many pages, and it is ideal for uncoated paper grades as the paper absorbs the glue well, which ensures good adhesion. Coated paper on the other hand does not have the same ability to absorb the glue.
The actual binding process involves first collating together the inside pages of the product, and then shaving off three millimetres or so on the spine side. Adhesive is then applied and the cover is attached. Perfect binding is a common technique in hardback and paperback book production.
– Thread-binding – also called textile binding – is the very strongest binding technique, as well as being one of the oldest and most expensive. Take an old book down from the shelf and check the binding and it is very likely to have been stitched with a linen thread in the spine. The method involves putting the printed and folded sheets in the right order and then, rather than gluing or stapling them together, stitching them together at the spine. The cover is then glued on. The inside pages are first trimmed down to the required size, depending on whether the cover is hard or soft. Thread-binding is suitable for all paper grades as no adhesive is used.
– Thread-sealing is a combination of thread-binding and perfect binding. Each sheet section is individually stitched on the spine side using a plastic thread, which melts together with the adhesive. Once all the sheet sections have been stitched, they are glued to the cover. As with perfect binding, uncoated paper works well with thread-sealing as the glue absorbs into the sheet and ensures a stronger adhesion with the cover.
– Spiral binding comes in several different variations: wire-o binding (which has been used for this guide), classic spiral binding and GBC binding are just a few. Two things they all have in common are the fact that they are trimmed down to the right format before binding, and consist of loose sheets that are hole-punched and bundled together. The spiral binder is then attached, and these come in all kinds of shapes and colours. |
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Hole-punching is of course pretty much self-explanatory. Holes are punched into the outer edge of a document so that it can be kept in a ring-binder. Rather than a conventional office hole-punch, the graphics industry instead uses a special drill to put holes in the sheets. |
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If users have to be able to tear pages, coupons or similar from a document, perforation is a common way of making this easier by providing a row of small holes. Perforation is often performed on a flat bed press with a perforation rule, or using a scoring tool – which is not unlike a toothed saw blade. |
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The very last stage in most print productions is the final trimming. The sheets have already been cut and trimmed several times depending on the size and method, but not to the exact format. Now that the product has been printed and bound, it has to be given a final trim to ensure the edges are attractive and even. |
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