When I was getting my files ready to print, the cover was giving me a bit of trouble. I did a wrap around cover, which means the front, back and spine are all one image. This can be difficult for a few reasons, but what really threw me was that you need to know the size of the spine. Createspace, the company I'm publishing through, has a very simple way of multiplying the page number with the size of each piece of paper. You'd think that would be simple right? Well, everyone jokes that writers cant do math, and for me it's no joke. Apparently even with a calculator I managed to get it wrong the first time.
Another problem that I ran into was the fact that the book needs a bleed. In other words, if I want the image to go right to the edge of the book, I need to make it a little bit bigger than the size of the finished product. That way, the printer has a little bit of wiggle room to cut the page to size without leaving an ugly white line along the edges, which would look very unprofessional.
At first I made my file in Photoshop. I used guides to block out the front, back, spine and bleeds. However, when I sent in the file, they didn't recognize it as having a bleed. Instead, it just looked like the file was the wrong size to them. So, I decided the easiest thing to do would be to take the file and rebuild it in InDesign. I mentioned before that InDesign is a very powerful program, and one of the things that it can do is figure out all that bleed stuff for you. It can make a file the perfect size and then around the outside it will make an extra box that tells you exactly where you need to bring the image out for a bleed. When you export it as a PDF, it keeps that information and sends it to the printer. Happily when I sent this version of the PDF, the file was perfect as far as the printer was concerned.
One fear I have is that sometimes the colours in Indesign don't print quite how I expected. Since I had to add colours that matched the original cover image, I'm hoping that they will turn out alright. That's one of the things I'll be looking for when I get my proof copy back in a couple of weeks.