Instructions provided describe how to set up ArcMap page and printer settings. This article contains conceptual and procedural information on how to properly set up the map page and printer paper sizes for ArcGIS 9.x.
ArcMap was designed so that the 'Map Page' and the 'Printer Paper' are separated. Most Windows applications are like this; the difference is, in most other Windows applications, those two areas always match. Microsoft Word, Outlook, Excel spreadsheets, and so forth, are always 8.5" x 11" and the default printer and default paper size is always 8.5" x 11". Since ArcMap maps are usually NOT in 8.5" x 11" format, these need to be given consideration and be matched.
This has been simplified by the inclusion of the 'Use Printer Paper Settings' check box on the Page and Print Setup dialog box. This creates the map page at the same size as the printer's paper, allotting for margins and non-printable area. ArcMap gets the page size and margin information directly from printer driver and the paper size selected.
When 'Use Printer Paper Settings' is checked on and the map document is saved, that information, including the printer selected, paper size and paper orientation, are all saved to the map document. When that map document is opened again, ArcMap looks for the printer and paper size information stored in the map document and matches it with the installed printer, retrieving it by its shared name, and reloads the map document identical to the last instance.
If ArcMap cannot find the same printer, for example, if someone else who doesn't have access to the printer, or if the printer is replaced, ArcMap turns off the 'Use Printer Paper Settings' option and open the map document, but does not change the actual map page size itself.
Another important setting on the ArcMap's Page and Print Setup dialog box is the 'Scale map elements proportionally to changes in page size' option. If the map has already been created and it needs to be scaled up or down to match the new page size, select 'Scale map elements proportionally to changes in map size' at the bottom of Print and Print Setup dialog box.
This scaling functionality is fairly accurate; however, it is a good idea to check the map before printing as some map elements may need to be adjusted.
Verify 'Page and Print Setup' has 'Scale map elements...' turned off after the scaling is applied. This option should only be checked on when the map page size needs to change.