How Crossovers/Gutter Jumps are Printed and Bound
I was asked the other day about producing a calendar for 2012. The unique challenge with this project was that it wasn’t a typical template calendar and that its design involves fashion photography that crosses over the spine onto the page beneath.
Large images that cross over the spine/gutter in the binding process are known as a ‘gutter jump’ or ‘crossover’.
This design is used frequently in the magazine and book publishing business, but it may be relatively unknown to most graphic designers or photographers as to how it’s produced. It may be one of the ultimate challenges for a high quality commercial printer to do successfully. It relies on every department (prepress, press, postpress) on doing there job exactly to specification to pull off a successful quality reproduction.
This post will cover the intricate details on how the images successfully register/line-up and how the correct color happens on press.
Let’s start with the basics of page layout.
Books, magazines, calendars and other publications that are bound are printed in signatures. Signatures are a specific group of pages, usually in groups of 16, that are laid out in a specific position on the press sheet (8 pages per side of press sheet). After the sheet is printed it is folded in half three times to a size just larger than the final trim size. Multiple signatures will produce a book of 48, 64 or 96 pages. All books are printed this way and usually will consist of signatures in either 8 page, 16 page or 32 page forms.
This is the page layout for a 16 page signature. This is the front side of the press sheet – note page numbers and pages are positioned head-to-head:
This is the back side of the press sheet – note page numbers and pages are positioned head-to-head:
Prepress will use this layout to precisely position/align the clients’ successfully prepared PDF files. The layout will change slightly if the intended publication will be perfect bound versus a saddle stitched publication.
Fortunately, all crossovers/gutter jumps are always positioned on the same side of the press sheet allowing for easier color matching of images on press. Therefore, in a 16 page signature, there are 8 pages per front and back side of the press sheet; 8 pages = four page spreads.
Let’s now look at page spreads and see how they are positioned in the signature.
Let’s start with the four page spreads on the BACK side of the form:
Here’s the positioning of these four spreads on the BACK side of the 16 page signature. Notice how precise the ink densities are required to get the proper color to align across the width of the press sheet:
Here are the page spreads for the FRONT side of the form. Notice the page spreads for pages 8-9 do not require any special attention, as well as page 1 and page 16:
The FRONT side of the 16 page signature is a little more forgiving. As you can see, there are only two page spreads that need critical alignment. However, they are right inline with the ink key zones and do not require as much precision with ink densities.
After the sheets are all printed, the printed signatures move to the folder where they are to be folded. The sheets are folded with three right angle folds. The length of the sheet is folded in half, then right angled to another folding gate where it’s folded in half and another right angle to finish the third fold in half. The precision of the folding equipment is critical to make sure the folds are in the exact position on every sheet. This ensures that the finished crossover is aligned perfectly.
NOTE: In the case of printing your magazine via heatset web, the folding process will occur in-line after web exits the chiller rollers.
Illustration of three right angle folds for 16 page signature:
Overall, gutter jumps/crossovers are a lot of fun to produce and really test the craftsmanship of a commercial printer. Let’s also not forget that the printer’s equipment be updated and in great working order – the registration between the press and folder is critical.
What’s your experience with designing crossovers? Do you have one in your future design?
Photography courtesy of Mike Byerly Photography