Exported Jpeg error? Does not look like edited Raw

priort · November 16, 2022, 7:03am

AP popped up a few hours ago…

He had some interesting comments if you can filter it out from the overall WTF are you idiots doing…

github.com/darktable-org/darktable

[DT Master 4.1.0] color balance rgb perceptual briliance grading highlight slider creates artifacts

opened 07:11PM - 08 Sep 22 UTC

s7habo

priority: high feature: redesign difficulty: hard bug: pending release notes: pending

**Describe the bug/issue** If the highlights of the photo are close to the li…mit of dynamic range, the highlight slider of the perceptual briliance grading in the color balance rgb module produces artifacts when a certain threshold is exceeded. This only happens in the default _darktable USC (2022)_ color space. In JzAzBz (2021) color space the slider behaves as expected. **To Reproduce** 1. increase the exposure of the photo with exposure module until the highlights are at the limit of the dynamic range. 2. in the color balance rgb module, increase the value of perceptual brilliance in highlights using the highlights slider. 3. After a certain value, the artifacts - wide white spots - appear (see screenshot/video below). **Screenshots** ![Artifact](https://user-images.githubusercontent.com/38165484/189203438-3bfec8e8-b120-48c1-b5e0-4d2a1d719115.jpg) **Screencast** Short demo: https://user-images.githubusercontent.com/38165484/189202459-4b598eb2-263c-421e-ba1c-e04402929b3e.mp4 **Platform** _Please fill as much information as possible in the list given below. Please state "unknown" where you do not know the answer and remove any sections that are not applicable _ * darktable version : 4.1.0~git272.5a1a1845-1 * OS : Linux * Linux - Distro : Ubuntu Studio 22.04 * Memory : 31,3 GiB * Graphics card : NVIDIA GeForce GTX 1070/PCIe/SSE2 * Graphics driver : 470.141.03 * OpenCL installed : yes * OpenCL activated : yes * Desktop : KDE-Plasma-Version: 5.24.6 **Additional context** I can't say for sure, but I suspect that this problem may be related to the https://github.com/darktable-org/darktable/pull/12233 since this behavior appeared after that commit.