Bloom broken with some tonemappers

Askeladd

Member
Nov 14, 2025
16
9

The dark sky with stars look weird when using some tonemappers with bloom enabled.

The issue is subtle on SDR monitors (still visible if you zoom in), but it is really visible on HDR monitors (see second post below)

Tonemappers affected : Hable, Gran Turismo, ACES, Uncharted, Linear, Reinhard Luma & Simple (subtle)
Tonemappers unaffected : ACES fitted, Filmic, Agx

Workaround : Disable Bloom or switch to one of the three unaffected tonemappers or disable HDR in the display settings for this game

Hable tonemapper with Bloom enabled: (issue)
KSA 2025-11-14 05ː53ː02.png

Aces Fitted tonemapper with Bloom enabled: (no issue)
KSA 2025-11-14 05ː57ː05.png

See this post in the "Suggestions forum" about HDR on the discord server
 
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The bug is quite subtle on SDR monitor (but still visible if zooming in), but it is way more visible on HDR monitor:

Here is a picture of my HDR monitor so you can see the issue more easily
image.png

BTW, is it normal Bloom add a weird halo around the spacecraft ?
I guess that's what bloom does, but it looks weird when ontop of the dark sky, imho
 
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I get the same thing.
I like the default tonemapper so I prefer to disable bloom, as I also find the halo around the craft to look weird

Even in SDR this "ruins" the dark sky on OLED monitor (they have perfect blacks m, but here the broken bloom make the dark sky half grey)
 
There's nothing wrong there, it's a limitation of 8-bit per channel color only having 256 levels of brightness. What you're seeing is a transition between 0 and the next lowest value (1/255).

The issue with your HDR mode is extremely poor display calibration coupled with KSA not supporting HDR output, so you shouldn't be using HDR with it in the first place.
 
There's nothing wrong there, it's a limitation of 8-bit per channel color only having 256 levels of brightness. What you're seeing is a transition between 0 and the next lowest value (1/255).

The issue with your HDR mode is extremely poor display calibration coupled with KSA not supporting HDR output, so you shouldn't be using HDR with it in the first place.
Then explain why this doesn't happen with ACES Fitted but does happen with Hable or other tonemappers ?

Sans titre.png
 
Because the toe of the tone curve works differently for each of them. Some transition to black very gradually, others very abruptly. In the former case, you'll notice the issue, and in the latter case you won't.