The following are the steps I followed to setup printers through SSH Tunnels at BNL. I assume that you have the BNL Proxy Tunnel setup and running. In particular, you have opened port 1631 of your local computer to talk to the printer server cups.phy.bnl.gov through port 631. I also assume that you are using a Mac.
go to System Preferences
click on Print & Fax
click add printer (the "+" below the list of printers)
click on IP in the newly popped-up window
The attached picture is the screen shot of setting up the printer Phenix_4730MFP. To see the list of available printers, point you web browser to "localhost:1631" and click on "Printers" on the top right of the page.
The items "Protocol" and "Address" should be exactly as in the screen shot. You choose whatever "Name" and "Location" you want. The printing queue should be "/printers/${name of the printer}", where you should substitute ${name of the printer} to the name of the printer you want to add (duh!). Although the printer driver is listed at "localhost:1631/printers", I simply choose one from the "Print Using" list that closely match the "Description" of the printer.