One area of significant confusion is how to make the correct artwork adjustments for Perfect or PUR bound jobs when there are images or text that cross over from the left hand page, across the spine, to the right hand page. Once you appreciate that the book cannot be opened flat (without irreparably breaking the spine and pages becoming loose) it is a short step to understand that part of the page is lost within the valley the spine creates. To create the illusion of an image or text that is continuous across the spine, some adjustment is necessary.
The effect is appreciably worse when there is a cross over image on the inside front/inside back cover and the first/last page of the text block. This is because the cover is glued around the spine of the text block and a hinge is created in the cover some 5mm or 6mm from the spine back (check the hinge dimensions with your printer). In this way, without artwork adjustments, approximately 12mm of the centre of the image would be lost because the glue necessary to create the hinge will ‘hide’ the central area, 6mm of the left page and 6mm of the right page, of the image.
The principle of adjusting the artwork for the cover or the text is the same, only the extent is different.
cover artwork adjustments
The figure below shows an image that is intended to cross over the inside front cover and first text page of an A4 brochure. With bleed, the dimensions of this image will be 303mm x 426mm.
Assuming a 6mm hinge on the cover, the steps to follow are:
1. Duplicate the image in the same position over the top of the original. Let us say that the duplicate will be used for the left hand page and the original for the right hand page.
2. Select the left hand page and drag the right hand side of the image box over to the centre of the spread.
3. Select the right hand page and drag the left hand side of the image box over to the centre of the spread.
4. Select the left hand image and move the image 6mm towards the left (so if the image is set at x:0mm, adjust to x:-6mm)
5. Select the right hand image and move the image 6mm towards the right (so if the image is set at x:213mm, adjust to x:219mm)
When finished, the image will look as below
This will work in the finished book because the creation of the glued cover will remove 12mm (again please check this dimension with your printer) from the centre of the spread and you will be left with the result you require.
text artwork adjustments
For the text, follow the same steps as for the cover. We would recommend that only a 2mm movement is required but you should check with your printer. When finished, the image will look as below.