Graphic imposition is done before printing. This is where you define how the print itself should be placed over the entire printing sheet. In other words, this is where you plan the area of the printing sheet, both to make the best possible use of it, but also to ensure that the printing sheet can be handled in the subsequent finishing processes. For example, if you're making a brochure or a book, it's crucial that the pages are staggered correctly so that the pages are in the right order.
