NotMyFault Posted February 21, 2021 Share Posted February 21, 2021 Hi, the "difference" blend mode is great to spot any differneces between 2 layers. Identical pixel blend to pure black, any difference are rendered to non-black, which can be amplified by a levels adjustment. Unfortunately, this will only work when alpha is 1 (pure white). Otherwise, he blend formula will lead to non-zero results for color and below-one results for alpha, making this useless for spoting differences. My question: Is this by design? To be useful for spotting differneces, i would expect it to deliver RGB=0 and alpha=1 if both layers have equal RGB and alpha values, for those cases where alpha <> 1, too. In the picture, you can find a gradient in the bottom from white to black, 100% opacity In the top, a copy of the gradient with 50% opacity On the left, the original gradients. On the right, i added a copy with blend mode "difference". As you can see, only the right bottom quarter shows pure black as expected. The right upper quarter shows non-black, even if the layers are 100% identical both in RGB and alpha. blend mode difference and alpha.afphoto Quote Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 iPad Air Gen 5 (2022) A2589 Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps. Link to comment Share on other sites More sharing options...
NotMyFault Posted March 15, 2021 Author Share Posted March 15, 2021 Nobody interested? Quote Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 iPad Air Gen 5 (2022) A2589 Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps. Link to comment Share on other sites More sharing options...
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