Printing designs often require a critical cross alignment, also referred to as a cross over, between pages. There are a number of planning tips that will help the designer and printer to achieve the desired end result.
The best folding layout to insure accurate cross alignment is a parallel or double parallel fold. This signature design requires folding only along the spine of the signature, helping to insure the desired cross over between pages. If a quarter fold design is used, the flat text sheet must be folded in two directions (head to foot and spine to face), generating an increased opportunity for register variance. A quarter-fold design creates registration creep in two directions, while a parallel or double parallel fold creates creep in only one direction.
In order to achieve the desired cross alignment between text pages in an adhesive bound book, the designer or printer must take into account that the spine side of the page will receive a 1/8” grind off. The grind off is done in order to expose fiber in all the pages of a folded signature to the adhesive. Failure to incorporate a 1/8” spine grind off into the page layout will result in cross alignments that will be misaligned as much as ¼”. Ask your Allied Representative for assistance with any cross alignment questions you may have.
In order to achieve the desired cross alignment between the inside front cover and the first text page of the book, or the inside back cover and last text page of the book, the designer or printer must keep in mind that the text pages will have the 1/8” grind off and the inside covers will have ¼” side glue hinge. Failure to incorporate each of these dimensions into the planning process will result in cross alignment that is off as much as 3/8” from the anticipated result.