What Actually Happens at the Printer?
Background: I am preparing a Crown Quarto size (7.44” by 9.68”) book for submittal to LuLu Express. I have previously sent a final (for another Crown Quarto size book) and a first draft of this book, so generally know how things work from the LuLu Express end.
In my prior submittals, I have followed the template, PDF guide and FAQ on how to prepare the interior. That is, I added 0.125” “bleed” to all four edges, so that the submitted PDF is actually 7.69” by 9.93”. As an aside, my submitted books do not actually have any bleed-style content (all text/images stay well-away from the edges and inside the normal text area).
Question: I know nothing about what actually physically happens at the printer. A safe assumption is that they are not printing on 7.69” by 9.93” paper and trimming 0.125” off each side. So what is really happening?
One thought is that they have actual Crown Quarto size paper. Their printer prints the document at actual size, centered so that the left and right 0.125” are off the printed page. The bleed is necessary (for a book with actual bleed) because the left and right edges might be off by some small amount. As far as the top and bottom 0.125”, maybe they can tell the printer “ignore the top 0.125 when printing the document page”, which again handles any actual bleed. The problem with this theory is that it is inconsistent with my experience, where the book I received was about 0.2” shorter than Crown Quarto size. Thus, I doubt very much they are using Crown Quarto size paper.
That means (I think) there must be actual trimming involved, with some industrial style trimmer and some required allowance for “off by a bit” trimming. Which makes me wonder whether they are just printing on 8.5 x 11” paper and trimming as needed.
And then I wonder what happens when LuLu (and thus the printer) receives a PDF that is sized at actual Crown Quarto size: 7.44” by 9.68” (i.e., no bleed allowance). Do they, by automation, somehow know to trim accordingly?
Partly I am just curios. And partly, I am wondering whether there is any actual downside to submitting a (non-bleed style) PDF at actual Crown Quarto size.
If there is someone who knows how this all actually happens
at the printer, I would be very interested in knowing.