Saddle stitching is mostly used for magazines, picture albums, primary and secondary school books and periodicals, etc. Most of these books and periodicals have 1 to 4 print sheets, and the paper used is 60-80g/m2 offset paper. High-end periodicals and magazines mostly use 105-157g/m2 coated paper. If you carefully observe the semi-finished products folded and nested together, you will find that there is an accumulated width between the stacks. For every 1mm increase in the book thickness, the horizontal superimposed width of the spine will increase by 0.5mm, and this width increases with the increase in the number of stacks. When there are less than two printed sheets, the accumulated width at the binding edge of the spine is about 2mm. After saddle stitching, the superimposed pages at the spine will be tightened a little by the wire nails.
When the pages are cut into finished products, the innermost pages will be cut off by about 2mm. The impact on the page quality is not too obvious. However, when the number of pages increases to 4, the accumulated width at the spine of the book or periodical usually increases to 3-5mm. The innermost pages are invisibly squeezed out, and a trapezoidal edge is formed at the cutting edge. Due to the fact that the four pages cannot be placed closely together during the binding process, sometimes the width of the overlaid spine can even exceed 5mm. Moreover, this width difference cannot be resolved. When cutting, the finished edge of the inner page that was squeezed out was cut off by 5mm. When opening the finished book, the inner part of the finished page was cut off, and some framed edges of the picture were no longer centered. The most serious issue is that some page numbers have been cut out, and some have been clearly moved towards the cutting edge. The positions of the page numbers throughout the book are severely off, directly disrupting the overall design of the pages.
How can this problem be solved? First of all, it is necessary to understand the features of the product, the type and count of paper selected. For general magazines with only 1-2 pages, 60g/m2 offset paper can be used. The normal layout method can be followed, with the page center centered. If it is a book or periodical with four pages, regardless of the type of paper used, when making up the layout, the core of all pages of the third page should be moved towards the binding edge by about 3mm, and the core of the fourth page should be increased to about 5mm on this basis. There is no need to worry about unexpected quality problems caused by the movement of the core. If it is a high-end picture magazine, you can use a computer typesetting system to gradually move the pages of the 1st to 4th pages, page numbers 1 to 32, and 33 to 64 towards the binding edge. Start from the 32p and 33p of the inner pages, move by up to about 5mm, and gradually move until the center position of the 1p and 64p. In addition, before making the layout, a complete sample book can be folded on the required paper first, and the width of the spine after superimposition can be measured to obtain accurate data, and then production can be carried out. This can reduce unnecessary waste.
