ACI XCIX-0001 Posted January 2 Share Posted January 2 (edited) can someone explain why on this image when you take it in affinity photo or krita and you take one of the highest luminance bright with the color picker, you replicate the color with 2 brush lines, and the lines are not white but they are black, like to show that the color are out range or something ? is it related to the negative values management you talked about earlier ? do you know how to recreate these colors at these luminances in affinity, krita or, any other software ? Edited January 2 by ACI XCIX-0001 links Quote Link to comment Share on other sites More sharing options...
NotMyFault Posted January 2 Share Posted January 2 Hi and welcome to the forum. i cannot reproduce the issue, maybe i missed some details. can you give the exact x/y position of the pixel you are sampling from? which color picker do you use, the color picker tool, or the color panel picker? which OS, GPU, display do you use? is your setup HDR capable end-2-end? 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...
ACI XCIX-0001 Posted January 2 Author Share Posted January 2 thank for answering ! solved by using the 32 bits rgb values and intensity in the color selector. by the way the software is completely wild, the only one to directly open .jxr hdr screenshot to allo to directly edit it on hdr display int the viewer ! Quote Link to comment Share on other sites More sharing options...
ACI XCIX-0001 Posted January 2 Author Share Posted January 2 strange how all the primaries supports 60 value but the pure blue can only go to 2 before it clips to purple with more than that. do you know why ? Quote Link to comment Share on other sites More sharing options...
NotMyFault Posted January 2 Share Posted January 2 Affinity allows RGB values between 0.0 and 100.0 But no display can render such colors values. There is a maximum nits value configurable in 32-bit preview. When memory serves me well SD displays typical 200-400 nits, HDR displays 800-1600. so you might get lightness values to 4.0 or 8.0 actually rendered, the rest can only be clipped. Depending on color profile of Display clipping may occour asymmetrical per color channel. 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...
ACI XCIX-0001 Posted January 2 Author Share Posted January 2 a ! ok thank for your detailled explanation ! the strange thing is that the red, yellow, green, cyan hold up until 60 after that they clipped to another color but the blu only clips after 2. the display use here and configure on affinity is a ks9500 1400 nits 20% windows peak brightness|luminance in hdr mode on windows, full, rgb, 12 bpc, 2160p. the color range used on affinity is rec. 2100 st. 2084 pq. do you know if there is a relation in all of that explaining this difference of threshold before clipping ? meaning why does the blue clipped way faster than the other colors ? could it also be related to the rec. 2100 color space because blue reaches the end of the triangle sooner in terms of wavelenght ? Quote Link to comment Share on other sites More sharing options...
NotMyFault Posted January 2 Share Posted January 2 I need to check on my Mac later how Affinity behaves in such extreme situations. Possibly a bug (on specific OS), possibly by design. 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...
ACI XCIX-0001 Posted January 2 Author Share Posted January 2 thank ! waiting for your feedback ! Quote Link to comment Share on other sites More sharing options...
ACI XCIX-0001 Posted January 2 Author Share Posted January 2 apparently it works the same either on krita or on davinci resolve : blue clips before the 2 other primaries. but still interested if you have an explanation about that ! edit : resolve does not clip the colors with the value slider in fusion but if you take a screenshot and analyse this hdr .jxr in affinity with the color picker, you will notice that resolve actually uses some strange negative values for the primaries to avoid clips them. you can reproduce the same high value color but as soon as you replace the negative primaries values, the blue turns purple. Quote Link to comment Share on other sites More sharing options...
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