“Imposition” and “backup” refer to how the front of a printed piece is oriented to the back. In the case of a brochure, you normally turn it over right-to-left (like you turn the page of a book) in order to have the back side read correctly — not upside down. Seems simple, until you get to a postcard where one side is layed out in landscape (horizontal) orientation, and the other side in portrait (vertical) orientation. We use our best judgement when imposing a job, so that it backs up in the most natural or normal manner. Some designs, however, contain both portrait and landscape elements on both sides, making it difficult to make a clear call. When reviewing your proof online, we will always post the front and the back in the orientation that they will print in relation to each other. So, if page 2 appears upside down, that is how it will be printed on the back of page 1. (Some people want it that way, so that the recipient of the piece must turn it over top-to-bottom in order to read it correctly.) Be sure to print out a copy of your online proof, and attach the two sides to each other to create a “mockup” or “dummy.” This is especially important when a job will be folded.