Bug 503318

Summary:	"Night Light" functionality results in really skewed colors on my external display - first towards brown/green, then towards red/purple.
Product:	[Plasma] kwin	Reporter:	vriesk <v>
Component:	night color	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	nate, xaver.hugl
Priority:	NOR
Version First Reported In:	6.3.4
Target Milestone:	---
Platform:	Debian testing
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	drm_info output kscreen-doctor -o output kscreen-doctor -o output

Description vriesk 2025-04-24 22:42:58 UTC

Created attachment 180626 [details]
drm_info output

SUMMARY
"Night Light" functionality results in really skewed colors on my external display - first towards brown/green, then towards red/purple.

STEPS TO REPRODUCE
1. Set up some windows with different shades of gray.
2. Turn on "Night Light" in KDE settings, to some temperature lower than 4000K or so.

OBSERVED RESULT
As observed, grays and blacks start to really get miscolored when night light comes into play. Up to ~4300K setting or so, they look OK, but then they receive heavy brown/green tinting which then abruptly changes to red/purple tinting.

This abruptness is visible both when adjusting the night light temperature to lower level, or between a color gradient shown on a screen - blacks receive the final red/purple tinting much earlier than lighter grays.

This can be seen on this video: https://photos.app.goo.gl/K7D1Fauu5FnYRCjB8

Oddly enough, the bad tinting only happens for my external display; laptop's internal display looks fine.

EXPECTED RESULT
I'd expect the night light to gradually alter the colors of grays without any strange recolorings.

ADDITIONAL INFORMATION

Possibly related to https://bugs.kde.org/show_bug.cgi?id=500837#c2 ? 

Attached `drm_info` output.

Comment 1 Zamundaaa 2025-04-25 10:04:56 UTC

Please attach the output of kscreen-doctor -o

Comment 2 vriesk 2025-04-25 10:19:39 UTC

Created attachment 180634 [details]
kscreen-doctor -o output

`kscreen-doctor -o` output attached

Comment 3 vriesk 2025-04-25 10:23:25 UTC

Created attachment 180635 [details]
kscreen-doctor -o output

`kscreen-doctor -o` output

(now without terminal color escapes junk)

Comment 4 vriesk 2025-04-25 10:26:39 UTC

Comment on attachment 180635 [details]
kscreen-doctor -o output

>Output: 1 eDP-1

This is the laptop's internal display that does not have the discoloration problem.

>        disabled
>        connected
>        priority 0
>        Panel
>        Modes:  1:2560x1600@60!  2:2560x1600@48  3:1600x1200@60  4:1280x1024@60  5:1024x768@60*  6:2560x1600@60  7:1920x1200@60  8:1280x800@60  9:2560x1440@60  10:1920x1080@60  11:1600x900@60  12:1368x768@60  13:1280x720@60 
>        Geometry: 0,0 707x530
>        Scale: 1.45
>        Rotation: 1
>        Overscan: 0
>        Vrr: incapable
>        RgbRange: Automatic
>        HDR: incapable
>        Wide Color Gamut: incapable
>        ICC profile: none
>        Color profile source: sRGB
>        Color power preference: prefer efficiency and performance
>        Brightness control: supported, set to 25% and dimming to 100%
>Output: 2 DP-3

This is the external display with discolored night light.

>        enabled
>        connected
>        priority 1
>        DisplayPort
>        Modes:  14:3840x1600@60!  15:3840x1600@144  16:3840x1600@120  17:3840x1600@100*  18:3840x1600@85  19:1024x768@60  20:800x600@60  21:640x480@60  22:640x480@60 
>        Geometry: 0,0 3491x1455
>        Scale: 1.1
>        Rotation: 1
>        Overscan: 0
>        Vrr: Automatic
>        RgbRange: Automatic
>        HDR: disabled
>        Wide Color Gamut: disabled
>        ICC profile: none
>        Color profile source: sRGB
>        Color power preference: prefer accuracy
>        Brightness control: supported, set to 100% and dimming to 100%
>

Comment 5 Zamundaaa 2025-05-02 18:48:27 UTC

> Color power preference: prefer accuracy
Does the issue still appear if you set the output to "prefer efficiency" instead?

Comment 6 Bug Janitor Service 2025-05-17 03:47:06 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!

Comment 7 Bug Janitor Service 2025-06-01 03:47:32 UTC

🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.