Double Page Spead's with Saddle Stitch books.
I'm doing an A4 saddle stitched book and want to put an A3 image across the centre pages.
When I've tried pictures going across 2 pages before with saddle stitch books, a little bit of the image was missing from the middle. Probably due to the printing process?
I thought about putting a small blank vertical strip (maybe 2 or 3mm wide) down the centre of both halves of the image, hoping that this would be removed and not part of the image. I was going to try and order a proof and see if I managed to get it right, but with a colour book its going to be over £10 plus postage just to see if I'm right (or wrong.)
Is there a measurement for the amount which will be lost on each page?