I have to admit that when I saw the title I was expecting something 'garish' or gimmicky but to my surprise I found some very well done photos.
The colorization is well done and subtle.
Nice job.
OK, I'm running LR Classic not 6.12 but it should work the same.
Select all of the photos in the folder and then click on the '+' to create a new collection.
One of the options should be to 'include selected photos'.