Forget protein shakes and bodybuilding – in print, bulking is a very different phenomenon. And much more important!
If you’re designing a saddlestitched booklet of significant pagination, you’ll need to deal with it. The main symptom of bulking [also known as creep] is that the pages in the centre of your publication actually turn out a couple of mm narrower than those on the outer reaches.
This is simply due to the bulk of the inset pages of the spine.
Bulking occurs in large saddle-stitched products, since each section is progressively stitched inside the previous section. It varies according to pagination and paper thickness, but the inescapable fact is that when the spine is 3mm thick, the centre pages will be pushed out 3mm. Thus, a 210mm wide page will be 207mm in the centre. The 3mm is invariably lost from the fore-edge of the publication which can have dramatic consequences if you, for example, designed a bleed panel 4mm from the edge. When 4mm is cut to 1mm and we factor in machinery movement within industry tolerance, there’s not much left to play with.
So, if you have a thick saddlestitched publication on the go, give us a call to discuss before you finalise your layouts. We can help you avoid this, and many other pitfalls!