Within a few months of starting to use Lightroom, I was using it for all my printing. The Hartnell show is no exception. Printing from Lightroom has many advantages over printing directly from Photoshop. Parametrically specifying the margins means you can print a whole series of images without worrying about the detailed layout of each image. Lightroom can also print a whole series of images in sequence, so all you have to do during the process is shuffle paper.
Sharpening is another place where Lightroom shines compared to Photoshop. Since the right amount of sharpening depends upon the printer, the paper, and the viewing distance, I always leave sharpening until the end. Without Lightroom, the work flow is as follows: load the photograph into Photoshop, save it under a temporary file name so that you don’t inadvertently overwrite it, sharpen it, and print it. With Lightroom, you just pick the right check box. It’s true that Lightroom’s sharpening options are limited compared to Photoshop, but they’re good enough for most purposes.
Another advantage to printing from Lightroom doesn’t apply to the Hartnell show, because I’m not using mats; it’s the ability to add printed information off to the side or below the image. Lightroom’s flexibility on this point hasn’t quite progressed to the stage where you don’t have to write any identifying information on the print, but it eliminates a lot of the boring copying of information.
I haven’t used Aperture, but it probably has similar advantages over printing from Photoshop.