One of the first Colecandoo articles concerned the phenomenon of creep on saddle stapled books.

Since the writing this article, I felt it was time to revisit the topic, but provide some much-needed context and illustrations that may better show creep in action, how its effect can be minimised, and how printers normally compensate for it.

What is creep?

In simple terms, creep (also called Shingling, Thrust or Push-Out) refers to the effect of pages of a Saddle-Stitched publication being pushed out slightly once the pages are gathered for binding. This is best illustrated by taking several sheets of paper, folding them in half, and looking at the foredge (the edge opposite the binding edge).

The part illustrated in pink is the area affected by creep. If a publication won’t be post trimmed after it has been stapled (such as in this photo), then the book ends up with this somewhat untidy foredge.

However, where creep may affect content is when the publication has the untidy foredge trimmed flush after it has been stapled. Take the following example of a book that has been flush-trimmed on the foredge to 210mm width once folded.

If we open up the book to the centre spread, we can see from the ruler at the bottom that the width of the pages gets smaller as the pages get closer to the centre. This is because the foredge has been cut off.

On this example, each printer’s pair is reducing in size about half a millimetre per sheet, but over 8 sheets, that adds up to 4mm, meaning the outer sheets have a width of 420mm wide but the centre spread has a width of 416mm.

But 8 sheets would be 32 printed pages… if the document had double the page count (so 64pp), the centre spread would end up with a width of 412mm, effectively meaning any design that was 4mm from the trim on the left page and 4mm from the right page – when prepared in InDesign – would be lost. In the following example, that 4mm from each foredge will result in the page numbers being cut off (represented by the blue guidelines) during binding unless something is done to resolve the issue.

What happens when it goes to the printer?

There are five ways a commercial printer can handle creep:

1. Do nothing and print the artwork as submitted, potentially cutting off page numbers and design elements close to the foredge.
2. Ask the client to resupply the art with creep in mind. Will provide a better outcome, but resetting components of the artwork is most likely to frustrate a client.
3. The printer will manually adjust elements of the artwork for the client. Again, has potential for a better outcome… but now puts responsibility on the printer for any issues that may arise from missing or altered content.
4. Use an automatic adjustment that slowly moves the page content closer to the bind edge; or
5. Use an automatic adjustment that slowly adjusts the width of the artwork non-proportionally (that is, the height remains 100%, but the width would get fractionally smaller for each sheet)

Solutions one to three are self-explanatory, but solutions four and five are out of the client’s hands and the responsibility of the printer.

Complications from automatic creep adjustment

Imposition software moving pages towards the spine

A common method of compensating for creep is an automatic adjustment that is made during page imposition, and involves the imposition software gradually moving the artwork closer to the spine edge until the centre spread, and then the reverse movement on the remaining pages until the end of the book. Any overlap of the artwork is masked to the spine edge, so is not noticeable…

…unless there is artwork that goes over a left and right page. Take the following example where an element crosses the centre spread.

If this is a centre spread and 5mm creep adjustment was applied, this will move the art towards the centre spread and hide the remainder within the spine… but that looks like this:

The sign no longer appears correctly and doesn’t line up.

Imposition software scaling page widths towards the spine

Let’s take the same example but this time, use the method that scales the page widths. In this case 5mm of creep is required, the trim size is 210mm wide, so the software will apply a 98% left to right distortion to these specific pages.

The result is pretty good – it looks nearly identical to the intended artwork, and in most cases this method would be effective.

However, if the content that is being printed has design elements that must remain to accurate scales (such as a book about coins for numismatics or measurement templates for technicians) then this method should be reconsidered.

When would creep compensation be applied?

Admittedly the samples shown here are hyperbolic, and creep adjustment wouldn’t always be applied to every saddle-stapled product. There are several factors to consider, such as:

• The thickness of the stock. The thicker the stock, the more creep to consider.
• The page count. The larger the page count, the more creep to consider.
• The design elements. Are there design elements that risk being cut off if creep compensation isn’t applied, or does the design have ample room to compensate for this?

Was creep compensation was applied?

There are ways to determine if artwork had automatic creep compensation applied. If the artwork had common elements on the header or footer, then we can tell by looking at the book from a top down view. Take the following example:

I believe this book had creep compensation that because the header element is in the same position on each page, indicating that the art had moved closer to the spine. I draw this conclusion by looking at the line that is left as the headers all appear to line up (marked in pink on the image).

If creep hadn’t been applied, the header elements would gradually move towards the foredge until the centre of the book, and once trimmed, would look more like an arrowhead pointing towards the foredge of the book. Here are some other examples:

The arrowhead that forms can be used as greater than or less than signs to indicate whether more or less creep compensation is needed. For example, if the foredge is to the right and:

• the arrowhead is > (pointing towards the foredge), it means a greater amount of creep compensation is required;
• the arrowhead is < (pointing towards the stapled bind-edge), it means a smaller amount of creep compensation is required;
• no arrowhead and the design lines up, the correct amount of creep compensation was applied.

What should I take away from this article?

If you are designing a book that is intended to be saddle stapled, make sure the design keeps creep in mind. To be creep-safe:

• Avoid placing page numbers too close to the foredge;
• If there are elements that appear on the foredge (for example to colour code sections or pages) make them a generous size.
• Avoid placing images that cross over left and right pages;
• If you must place images that cross over left and right pages, consider using images that have greater tolerance for either misalignment (or if the automatic creep compensation method of moving artwork towards the spine has been used).
• Consider using an alternate method of binding, such as perfect binding or coil binding. Also consider placing a cap on the amount of pages a book should contain before using an alternate binding method. Yes, it is possible to have a 104pp saddle stapled book, but it can be unwieldy and have so much spring in it that it behaves like a catapult and won’t close nicely.

It is also worth pointing out that creep is just one factor that can affect a layout when design elements cross left and right hand pages, but that deserves an article of its own.