In online printing, page creep refers to the fanning out of pages that can occur when they’re folded and gathered together. As you fold more pages together, the thickness of the paper pushes the inner pages out. The amount of creep depends on the number of pages and the thickness of the paper.
Once the pages are folded and bound together, the final trim will cut off the edges of the innermost pages.
You’ll likely encounter page creep on Saddle Stitch Booklets. In custom booklets with up to 48 pages, the creep is often barely noticeable and doesn’t need to be accounted for. In booklets with more than 48 pages, compensating for the inevitable creep requires incrementally shifting the pages in order to end up with a consistent outer margin.
To avoid booklet creep, you can print your project with a different binding. Spiral Coil, Wire Coil and Perfect Bound Books are all great alternatives because their pages are not folded inside one another, so you won’t have to account for creep.
How Can I Adjust for Page Creep?
It is recommended to let the prepress department of your online printer to adjust the creep. However, if you’d like to do it yourself, you’ll need to know the thickness, or caliper, of the paper you will be printing on.
Once you have the caliper, follow these formulas to determine the creep of your pages:
- Number of pages/4-1 = Number of spreads
- Number of spreads x Thickness of paper = Total creep
For example, to determine the page creep on a 48-page book printing on 70# offset paper with a .005 caliper, the formulas would look like this:
- 48/4 = 12-1 =11 (11 is your number of spreads)
- 11 x .005″ = .055″ (.055″ is your total creep)
The reason the -1 is in there is because your first spread does not need to be adjusted for creep.
Adjusting for page creep manually on your own can be very time consuming, which is why it’s highly recommended to allow your online printing service’s prepress department to do it. Since most imposing software adjusts the files for creep as needed by simply entering the paper caliper, it takes them no time at all.