What is a crossover? A crossover is an image that crosses over the center-fold in a multiple page product, like a magazine, or catalog. Your printer will try to explain the difficulty involved in producing crossovers, but until you’ve been up-close-and-personal with a project  where the crossovers failed, you won’t completely understand.

Why is that a problem? This would be easier to explain if I were face-to-face with you, but since I’m not I’m going to attempt to lead you through a little demonstration.

1. Get a piece of paper, size doesn’t matter, but make sure you can fold it easily.
2. If your paper is the standard 8 1/2″X11″ fold it in half so it is now 5 1/2″X8 1/2″.
3. Keep the fold at the top and fold in half again to 4 1/4″X5 1/2″.
4. This particular fold would result in an 8 page form.
5. Now with the folded form, keeping the fold at the top, begin numbering the lower right hand corners–1 through 8.
6. Be sure to number both sides of the paper or you’ll only have 4 instead of 8. If you don’t get 8 you’ve missed something.
7. Open your sheet of paper.

Notice that on one side the page numbers are 1, 4, 5, and 8. On the other side the numbers are 2,3, 6, and 7. Now notice where the numbers are in relationship to one another. Numbers 2 and 3 are on opposite sides and so are 6 and 7. Are you with me so far?

Refold the paper along the original creases. Take a pair of scissors, or hand rip the folded top off. What you have is a little booklet with all of the pages numbered consecutively, but it wasn’t that way before you took of the top fold was it?  The only pages on the flat sheet that were next to each other were pages 4 and 5, which is what we call the center fold. The center fold is a breeze, but it is the other pages 2 & 3 and 6 & 7 that cause the problem. If the press operator is unable to make a near perfect color match from one side of the sheet to the other pages 2 & 3 for example when brought together for the final product will look very odd. One page could be more blue and the other more yellow. That would be an unfortunate look for a landscape, but a total disaster for a portrait. Color shifts are very visible in flesh tones.

If you look at the double-truck catalog spread example below you will notice a definite color shift in the background.

Assuming that this all made sense, what can a designer do about crossovers?