WHY YOU CANT GET A RAZOR EDGE - YouTube
October 7, 2019 at 7:35:49 PM PDT - permalink - -

- https://www.youtube.com/watch?v=WDmmxkn8t0c

GIMP - Sharpen & Unsharp Mask - YouTube
May 29, 2017 at 2:04:18 PM PDT - permalink - -

- https://www.youtube.com/watch?v=ilVJlob5jpU

Guide to Image Sharpening
May 28, 2017 at 11:48:32 AM PDT - permalink - -

- http://www.cambridgeincolour.com/tutorials/image-sharpening.htm

How to Use the Levels, Curves, and Sharpening Tools in GIMP - YouTube
May 26, 2017 at 12:46:46 AM PDT - permalink - -

- https://www.youtube.com/watch?v=lNoBjAaC0kU