Blur effect is brighter on 6.5 and doesn't match the theme

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1

I used the blur desktop effect on KDE Plasma, and today I noticed this effect looks out of place with my selected theme (Sweet KDE):

with_blur
with_blur2560×1440 288 KB

The blur causes the title bar, the bottom bar of the settings app, and the panel to look brighter gray and doesn’t really fit the selected theme. Without the blur, everything looks more coherent and fit. I tried configuring the blur, but it didn’t change the overall bright gray look, which doesn’t fit well.

It might be an issue with the 6.5 upgrade, since I noticed it just today, so I am either blind or the 6.5 update changed something about the blur effect. Does anyone know why the blur effect is brighter gray and how to make it look better with a darker theme like this?

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I noticed this too; I really don’t like it. The blur effect really shouldn’t be modifying the colours like that. It’s definitely tied to the blur effect; turning it off has colours show properly through transparent/translucent elements.

Screenshot_2025-10-25_17-30-49
Screenshot_2025-10-25_17-30-492560×1440 278 KB

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Sorry for so many messages mods. but im pretty sure its the contrast toggle thats been removed. when i use better blur kwin effect that does have that toggle available the blur returns to normal, but the moment i turn the contrast dial up in that 3rd party effect the same whitening effect happens.
tl;dr : contrast toggle has been force enabled which is causing this issue

1 Like
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after a bit of digging around i found that the improve contrast behind windows toggle is missing. this was the toggle that was giving me brighter blur in older plasma versions and it seems to be force enabled here. that might a cause…. im not entirely sure as im grasping at straws to find the issue

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5

Ive been having this exact same issue. I’ve tested a few themes (eg: chromosKDE, whitesur, oxygen) they all have the exact same issue of blur being disproportionately brighter after the update to 6.5

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6

I think you’ve got it. I’ve grabbed the Better Blur plugin and it looks good again. Hopefully the contrast toggle being left out was just a minor mistake that will get fixed soon.

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7

Having the same issue after updating to 6.5. Could you tell me where you got the Better Blur plugin please?

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GitHub - taj-ny/kwin-effects-forceblur: Fork of the Plasma 6 blur effect with additional features (including force blur) and bug fixes. I had issues ( wrong color ) with this combined with rebuilt GitHub - luisbocanegra/kde-material-you-colors: Automatic color scheme generator from your wallpaper for KDE Plasma powered by Material You but turned out to be its static blur default options.

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Thank you sir! Totally appreciate you!

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Blur is broken in all Plasma desktop, and that effect which helped to show text on transparent background is gone in 6.5.

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11

This is https://bugs.kde.org/show_bug.cgi?id=510818. We’ll investigate it.

3 Likes
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Is this a sign to fix whatever the underlying issue is for blur being broken in the first place ?

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20251029_145410
20251029_1454101920×2254 133 KB

also idk if its related but seems like the effect doesnt update properly with the background?
e.g. if i play a video and the color changes only a small rectangle of it would upadte

also, the issue is not visible on spectacle screenshot, kinda the reson i had to just take out my phone camera to capture it

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Debian 14 (Testing), Plasma 6.5.0 has the same problem, and I had to disable the blur effect until this is fixed (no big deal), because it was impossible to manually build “force blur” due to missing kwin package somehow.