NotMyFault Posted December 20, 2021 Posted December 20, 2021 Hi, there is a mismatch between specification and implementation of scope panel and intensity waveform (and others like RGB Parade). According to help: Available charts Intensity Waveform—displays a scatter plot of the luminance values of pixels in an image. The X axis gives the horizontal location of the pixel while the Y axis provides its luminance value. Observed: For pixels with black, intensity (luminance) is shown as thick line at 100%. Expected: 0% Screenshot is from iPad, same issue on Desktop. intensity waveform.afphoto User_783649 1 Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
User_783649 Posted December 20, 2021 Posted December 20, 2021 That’s actually very interesting! And what’s even more interesting, that there’s a little bug in the Color Picker that causes this problem. If you move sampler dot to the very black corner you’ll get H:0 S:100 L:0. I think it’s wrong. And the very black corner should actually be H:0 S:0 L:0 If you’ll move it tiny bit down from that, you’ll get H:0 S:0 L:0. Why S value getting changed from 0 to 100 here? Quote
NotMyFault Posted December 20, 2021 Author Posted December 20, 2021 The color sampling issue could be caused by the forced dithering of gradients. It leads to kind of colored noise added to the gradient, and if the picker is set to show values in percent, it could be rounded to HSL 0, 100, 0, in reality RGB 1,0,0 which looks almost black but is actually 100% saturated darkest possible red. Use Info panel or color panel, set to rgb sliders, set to 8bit, to see the correct color value. So this is unrelated to the issue I raised in this thread. Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
User_783649 Posted December 20, 2021 Posted December 20, 2021 I’m not sampling the color from the gradient. I’m manually set it via Color Picker. For both of the gradient points. Try set the color of the black point of your gradient to H:0 S:0 L:0 and you’ll see that those will drop to 0% in Scope. Quote
NotMyFault Posted December 20, 2021 Author Posted December 20, 2021 Not on my Windows PC. Whatever method i use: Fill layer with color set to RGB 0,0,0 or to HSL 0,0,0 or color wheel Procedural texture filter with RGB=0 and A=1 Channel mixer with RGB=0 and ALPHA=1 The scope gets to 100% for all pixels who are totally fully black. The scope panel updates without undue delay, so i can always see the line jump from almost 0 to 100 when i move the sliders. User_783649 1 Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
User_783649 Posted December 20, 2021 Posted December 20, 2021 @NotMyFault Seems like another issue with Windows version of Affinity. I’ve just checked on Mac. Works as expected. Strange. Quote
NotMyFault Posted December 20, 2021 Author Posted December 20, 2021 Yes, platform depended bug In my view the MacOS behavior is wrong too. H 0 L 0 should be intensity 0 (and not 100%) no matter what value S shows. User_783649 1 Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
User_783649 Posted December 20, 2021 Posted December 20, 2021 3 minutes ago, NotMyFault said: In my view the MacOS behavior is wrong too. H 0 L 0 should be intensity 0 (and not 100%) no matter what value S shows. Absolutely! If L equals to 0 in both cases, there’s no influence of S can make on how Scope level is calculated for this area. Quote
Staff Callum Posted January 5, 2022 Staff Posted January 5, 2022 I believe this behaviour is currently logged with our developers to be fixed in the future. NotMyFault 1 Quote Please tag me using @ in your reply so I can be sure to respond ASAP.
G0HLJ Posted March 6, 2022 Posted March 6, 2022 Changing to H0 S0 L1 puts the scope in the right place so they are 1 digit off Quote
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