We proof "top-to-top" (or "head-to-head"), which means the front and back of your proof will be printed so that the top of both pages share the same edge. You would flip the proof like the page of a magazine to read the reverse side. Page 1 represents the front design and page 2 represents the back design.
As a general rule, you should submit your files in the same orientation as you designed them in, as the proof will be made based on how you submitted your file. The illustrations below show how the front and back of your design will be printed based on the orientation of the proof.
Horizontal or Landscape Designs
The top of these designs is on the long edge.
Vertical or Portrait Designs
The top of these designs should be on the short edge.
Below is another way we can print vertical or portrait designs. While the top of this file type is on the long edge, the designs are oriented in the correct way so that they will not print upside down. When held vertically, both sides will be the right side up.