I am brand new at using Lightroom and have only used the Book module. I have selected the Standard Landscape size, which is 10" (25cm) wide x 8" (20cm) tall. However, the display of the page is not remotely that aspect ratio. Similarly, when exporting the book to a PDF, the PDF is not the proper aspect ratio. As a result, images that are supposed to be full-bleed (printed to the edge of the page on all sides with no margins) are displayed in the Book Module and in the exported PDF as having a margin at the top and bottom. Considering that I am starting with a Lightroom page display that is clearly not the same aspect ratio as the pages in the book, how am I to know how the book is to be printed?
I have contacted Adobe support about this. My query has been elevated once to a guy that I had to explain what an aspect ratio is. (I was very grateful that he was both smart and polite enough to ask.) He took remote control of my computer and saw that, indeed, the aspect ratio displayed in Lightroom and in the PDF is not the aspect ratio of the book. He has now escalated this situation to a higher level and I will wait to hear from Adobe.
In the mean time, any ideas?