Digital BW, The Print

I reciently posted an inquirey pertaining to the centering of an 
image using an Epson 3000. The method suggested by more than one of 
you was to add white to the side and end that is small, thereby 
forcing the image to apear centered. I can see where this would 
works. My question now is whether or not creating this extra size 
will cause unnecessary interpolation of the image, degrading it 
somewhat?