Page 66 - Photoshop for Lightroom Users – Scott Kelby 2nd Edition

Step Six:
If you want to use a second program to edit your photos, you can choose that in the Additional External Editor section. So, for example, if you wanted to
send your image over to a separate plug-in or another image editing application (gasp!), this is where you’d choose it. Just click on the Choose button over
there on the right, navigate your way to the program or plug-in you want to use, and then click the Choose (PC: Open) button, and that application or plug-
in will now be displayed under Additional External Editor (shown circled here in red). To use this second editor (instead of Photoshop), go under
Lightroom’s Photo menu, under Edit In, and choose the other application (in this case, it would be Topaz Adjust 5, or press Command-Option-E (PC:
Ctrl-Alt-E). Next, there’s a Stack With Original checkbox. I recommend leaving this on, because it puts the edited copy of your image (the one you sent
over to Photoshop) right beside your original file back in Lightroom. That way, when you’re working in Lightroom, it’s easy to find the edited copy—it’s
right beside the original (as seen in the grid here).