Three methods for High-Pass Filter with GIMP 2.10.32+

High pass is kinda isolating the details of an image. In here it is aiming at sharpening them. Another common use is to keep the details while correcting the surface. Think of the popular skin smoothing process for instance. The video may be a bit fast and in such case please pause or reduce the playback speed as suits you. No talking. No music (but it may change. I didn&find one that distract and irritate you yet. Sorry for that. ?). No temporization Often the effet may end up too aggressive and I usually set the opacity around 30% on the high-pass layer. 00:00 Disclaimers / Info 00:18 Method 1 - The Old 01:35 Method 2 - The New 02:30 Method 3 - The Best Method 1: ========= This is the method I learned years back from an article titled "Vidar’s GIMPy high pass filter sketch effect" available on gimp.org. Steps: - Duplicate your original layer twice (Ctrl+Shift+D ×2) - Invert the colours on the top one. (Colors → Linear Invert) (1) - Change its opacity to 50% - Apply a Gaussian blur (Filters → Blur → Gaussian Blur...). - Play around with the settings until it suits you. - Merge down. (2) - Apply the "Grain merge" fusion mode - Optionally you can play around with "Levels" or "Curve" to tailor the result. (3) - Optionally you can desaturate the high-pass layer too. (4) (1) If you follow the article I mention, you¬ice it may gives poor results. The inversion does not give that perfectly mid gray colour it should have. This is because old versions had only one colour...