Change Duplex/Simplex Printing Defaults on a Mac

Details

You can change the default via CUPS, which is the core printing system of Mac OS X. To do this:

1. Open Safari and enter the following URL http://localhost:631
2. By default, access to the CUPS page is blocked. To enable it, open the Terminal application and type sudo cupsctl WebInterface=yes. Enter the administrative password for your Macintosh when prompted and then refresh the Safari view.
3. With the CUPS web page open, click the Printers tab and then select the printer you want to modify.
4. On the Administration drop menu, click Set Default Options. This will show a new page with four menu headings (links); Options Installed, General, Banners and Policies.
5. Click General.
6. Scroll down until you see the Print Style menu. Select the printing you want - either 2 sided or 1 sided.
7. Click the Set Default Options button found at the bottom of the window.
8. When prompted, enter the account name and password that has been set as the administrator for this Macintosh then click Log In. The new default setting will be saved.