It could be in the driver settings. I'll use Lr Single Image for this discussion. For sheet size, in Page Set-Up (which takes you into the driver) do you select the "Sheet Maximum" option for the paper size you have selected? When you open Print Settings, for Layout, have you checked that "Border" is set to "None"? Then in the Lr print dialog do you have the 4 borders set to the same width? The combination of "Sheet Maximum" with Borders=None set in the printer driver and the borders all set to the same width in the print module of Lr should give you a full size centered photo. So for example, if you are printing a 13x19 sheet, in the driver reached through Page Set-up you would select A3+ (or Super A3, same thing), Sheet maximum, and in Print Settings Layout set Border to None. Then in Lr, if you want a one inch border, you would select 1 inch for all four dimensions, resulting in a printed area that is extremely close to 11 x 17 inches, and it should be centered.