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With PQ output 100% is the 203 nit reference white, so the 1600% hard limit capped a sigmoid edit at about 3250 nits while PQ reaches 10000. Raise the hard maximum to 5000%, about 10150 nits and so the top of the PQ range, and keep the 50-100% soft range so the slider is unchanged for SDR work. The tooltip now explains how to use the value for HDR output. Fixes darktable-org#22665 Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HsykTqvsWoMew3BXJWE2KA
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HsykTqvsWoMew3BXJWE2KA
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Oct 17, 2026
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Branch:
nicknezis:sigmoid-hdr-target-whiteSummary
Sigmoid's target white was capped at 1600%. With PQ reference white at 203 nits, that limits a sigmoid edit to about 3250 nits while PQ reaches 10000. The hard maximum is now 5000% (about 10000 nits), so sigmoid can fill the whole PQ range. The slider's soft range stays at 50-100%, so nothing changes for SDR work; HDR values are typed in (right-click) as before. The tooltip now explains that 100% is the 203 nit reference white and that 1000 nits is about 493%.
Referenced issue
This is distinct from #18271, which asked for a wider visible slider range.
Fixes #22665
Related: #20242
Checklist
src/tests/integration/where the pixelpipe is touched, ordarktable-clias a headless smoke test._(), new preferences are registered indata/darktableconfig.xml.in.RELEASE_NOTES.mdentry was added (only needed if fixing an issue in a release). Do not reference GitHub issues.Test instructions
Done so far:
git rebase --exec 'cmake --build build' master)darktable-clion a synthetic -10 to +12 EV ramp, exported as linear Rec2020 PFM: at 100%, 1600% and 5000% the peak is 1.00, 15.96 and 49.57, middle grey stays at 0.179, and the output is monotonic with no NaN or InfNot verified: the GUI slider itself, OpenCL, real raws, macOS and Windows. The params struct, its version and the defaults are unchanged; only the upper limit moved, so existing edits render the same.
AI assistance
The code, commit messages and this description were written with Claude Code. I reviewed the diff.