Readers that don't read the PNG cICP chunk show the PQ samples as if they
were sRGB (flat, washed out): expected for PQ PNG, but it surprises people.
Noted in What's new (with the gain map JPEG as the look-right-everywhere
choice), as the export dialog's HDR PNG hint, and in the option and encoder
docs. Review suggestion on #664.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>