Lightroom Classic, Preferences not clear - How do I add items to 'external editing'?

[Ken Nielsen]

I have Topaz software DeNoise and Sharpen but want to add Gigapixel to the list so I can get to it easily from within Lightroom while editing with the menu 'edit in...' but frustration trying to add Gigapixel to the list of external editors as Lightroom seems to not want to let me add another external editor. Goin in circles with this and don't want to cause damage because I don't know how to do this. What are the steps to adding an external editor to the list I get when option clicking on an image from within Lightroom? 

TIA,

Ken

{Moved from Lightroom Cloud to Lightroom Classic Forum by Moderator} 

[Jao vdL]

Go into Lightroom preferences. Go to the External Editing tab. In the additional external editor area hit choose (ignore what the popup says) and choose the gigapixel app from the filebrowser that pops up. For file format select TIFF, color space ProPhotoRGB, 16 bits/component, 300 for resolution, and ZIP for compression. Then from the popup select "Save current settings as new preset" and give it a new name. Now you should have a new edit in menu for gigapixel.

[Ken Nielsen]

Thank You, This worked! 

[Rob_Cullen · Accepted solution]

I have attached my notes on this topic in an attached  .docx document file. 

[Ken Nielsen]

Excellent and complete. Thank You, I'm up and running now.