Adobe Illustrator normally uses the default page size defined by the PPD file for the selected printer. However, you can change the media size to any of the sizes listed in the PPD file as well as specify portrait (vertical) or landscape (horizontal) orientation. The largest page size you can specify depends on the maximum imageable area of your imagesetter.
Note: Changing page size and orientation in the Print dialog box is for printing purposes only. To change the page size or orientation of your artboard, use the Artboard Options dialog box or the Artboard options in the Control panel. (See Edit artboards.)
Note the following when specifying the page size and orientation:

