A duplexer is available on the printer in the Law Library on the 5th floor near the reference desk. This means that you now have the option to print double sided.
The default is set to print single-sided printing. To change to duplex, start by selecting print as you usually would. In the print dialog box, select the Law Library printer (if there are multiple printers available, look for the one that says "LAWREF"). Then click the "Properties" button. Click on the "Printing Shortcuts" tab and select "Two-sided (Duplex) Printing" from the list. Click "OK" and then print as usual.
Note that the cost is still the same (7 cents per page/side), but doubled sided printing will allow you to conserve paper.