2016-07-11 by rdeloe1@...
Lew, another option if you want to stay in Lightroom is to use mogrify to add a border of whatever size and colour you want. For example, when I publish images to my web site, I don't like to put copyright information within the image, so Lightroom's standard watermarking tools aren't a good solution. I use a plugin to publish to Smugmug (the web hosting service), and that plugin runs the free ImageMagick tool called 'mogrify' to add a small white border outside the image area with the copyright information. (See any image at
http://www.robdeloephotography.com to see what I mean.)
The ImageMagick toolkit is incredible and powerful, so it might be that you can add the border during printing directly from Lightroom. I don't know because I only print using Quadtone RIP -- so I export TIF files for printing.
Last tip: if you try the ImageMagick mogrify tool, make sure to install Version 6. The latest version (7) does not include mogrify for some reason.