I'm pretty new to publishing so not sure of the correct terminology to use, so I'll start with my usual process.
I usually create a book (for this example an A5 portrait formatted book). The front cover (page 01) starts on the right side of a spread of 2 pages. With all internal pages then being a two page spread. Finally the back page of the book being the left side of the spread of 2 pages (page 16 for example).
My current book design however requires a single image to span across both the front and back cover as a single entity. (basically wrapping from the back to the front cover).
So my question is how do I approach this? I have a couple of thoughts and I don't know if either is the correct method in terms of efficiency or more importantly when it's handed off to a printing company, I get back what i'm expecting.
Thought 01 - As the front cover is page 01 and the back cover is page 16, do i have to duplicate the image and create 2 images split equally down the middle and paste the right side image on page 01, and the left side image on page 16? This seems very time consuming and causes big issues when editing the image after splitting it into 2 images. (i.e. changing the contrast twice for each half of the image, or worse having to split the image in 2 every time I replace / update that image)
Thought 02 - Do I just create a new master page for the book cover which is A4 Landscape (=2X A5 portrait) and treat the front and back cover as page 01? and therefore have no specific back cover page (page 16). Will this cause issues at the printing company end, as the cover page is now not defined as A5?
Any help would be greatly appreciated to how I move forward. Finally relating to this issue, what's the process when you need to design the spine of a thick hardcover book?