Bug 511600

Summary:	Desktop blur effect oversaturates colors
Product:	[Plasma] kwin	Reporter:	me
Component:	effects-various	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED INTENTIONAL
Severity:	normal	CC:	dev, madness742
Priority:	NOR
Version First Reported In:	6.5.1
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	An image showing how the desktop blur effect oversaturates colors on the logout screen. On the left are the expected colors with the effect disabled, on the right are the oversaturated colors.

Description me 2025-11-04 04:43:49 UTC

Created attachment 186477 [details]
An image showing how the desktop blur effect oversaturates colors on the logout screen. On the left are the expected colors with the effect disabled, on the right are the oversaturated colors.

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SUMMARY
The desktop blur effect oversaturates colors.

OBSERVED RESULT
The right side of the attached image

EXPECTED RESULT
The left side of the attached image, but blurred

The image uses the logout screen as an example, but KRunner windows and Plasma popups also get oversaturated, it's just less obvious.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.5.1
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.6-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 24 × 12th Gen Intel® Core™ i9-12900K
Memory: 48 GiB of RAM (46.8 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3080

Comment 1 madness742 2025-11-07 10:08:11 UTC

I can confirm. 

I've noticed this since upgrading to Plasma 6.5.1, Plasma 6.5.2 hasn't fixed it either.

Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.2
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.7-300.fc43.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 32 × AMD Ryzen 9 7950X3D 16-Core Processor
Memory: 64 GiB of RAM (62,4 GiB usable)
Graphics Processor: AMD Radeon RX 7900 XTX

Comment 2 dev 2025-11-07 16:49:09 UTC

I believe I saw someone describing a fix for this on Reddit, here: https://www.reddit.com/r/kde/comments/1oihemv/plasma_651_blur_saturation_changes_and_how_to/

Their steps to fix are these:
For those on 6.5.1 who want the old look back:
    Edit ~/kwinrc
    Under [Effect-blur], add Saturation=1
    Restart (or log out/in) 

There's also talk of a slider that may adjust this in the future, but it wasn't merged

Comment 3 me 2025-11-08 00:01:56 UTC

It sounds like this is intentional and they're just waiting for a major release to add the settings widget to control it. I wish they'd kept it at 1 for backwards compatibility, but I guess this is solved now.