Sharpening Your Image: High-Pass Filter vs. Unsharp Mask. Tips by Christopher O’Donnell 13inShare In the world of photo editing, sharpening is the tool that you love to hate. It can easily turn your beautiful photo into a harsh, unattractive image if you’re not careful how you approach this. Episode 164: High Pass Sharpening. Download the Video! (16:13 30.9 MB)Download the companion file! (49.0 MB)Download the torrent file! Sharpening is a part of nearly every image processing. Selective sharpening allows to sharpen the important structures without to “enhance” the noise in the image. Discussing Sharpen in darktable.