>>456975
>printer hasnt responded yet
That's your answer. I'm going to guess you have images that spread across two pages and want to know how much space to leave between when you cut them in half. The answer is you can't know exactly. That depends on where they are in the book. Prepress software will automatically calculate how much to subtract from the "middle" in order to keep the outside edge consistent for cutting.

Of course I'm guessing what you want because your post doesn't really describe the problem you're having. You can make a good guess by doing some math yourself but I suspect you wouldn't know where to start...

>>456992
why be a dick?
you dont have to guess shit. i have spreads, they want pages. thats the fucking problem, dickhead.

>>456975
internet suggests some types of perfect binding dont require any bleed at the gutter laid out for single pages, and that some do.

should hear from the printer today.

crossing my fingers for the swiftest path forward.