Mac OS X 10.6: Creating a custom page size
If you want to print on paper that has an unusual size, such as an envelope or card, you may be able to choose the paper’s size from the Paper Size pop-up menu. To find the Paper Size pop-up menu, choose File > Page Setup. If you don’t see a Page Setup command, choose File > Print.
If you can’t find the size you need, you can create your own custom paper size.
To create a custom page size:
Open the document you want to print.
Do one of the following:
Choose File > Page Setup. Choose Page Attributes from the Settings pop-up menu, and then choose Any Printer from the Format For pop-up menu. Choosing Any Printer ensures that your document can print on any printer that supports the paper size you select.
If Page Setup is not available, choose File > Print. If the Print dialog contains only two pop-up menus and some buttons across the bottom, click the disclosure triangle beside the Printer pop-up menu.
Choose Manage Custom Sizes from the Paper Size pop-up menu.
Click the Add (+) button.
Double-click the name of the paper size, and type a new name.
Enter values in the Paper Size and Printer Margins fields, and then click OK.