HDR bloom: saturation-preserve option (bright coloured highlights wash toward white / pale) #998

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opened 2026-10-23 22:16:07 +00:00 by sky_line · 1 comment

sky_line commented

2026-10-23 22:16:07 +00:00

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HDR bloom (Photo Studio / Graphics: Lens > Bloom (HDR)) desaturates coloured highlights: a hot-pink glowing eye turns pale lavender with bloom strength 0.32, while the non-HDR glow keeps it saturated.

Why

Tone mapper shoulder: bloom adds energy on top of already-bright pixels; with a per-channel tone mapper (ACES Hill) the dominant channel saturates first while the others keep rising, so bright colours drift toward white.
Wide blur veil: at Scatter 1.0 the bloom is a wide blur that mixes the surrounding colours (purple fur, skin) and lays them over the source, lowering contrast and diluting the hue.

Wanted: a "bloom saturation preserve" option

Keep the bloom's hue close to its source: e.g. composite the bloom with luminance-based tone mapping for the bloom contribution, or re-saturate bloomed pixels toward the source pixel's hue/chroma (scaled by a strength slider, 0 = current look).
Optionally a hue-preserving tone-mapping path for highlights (luminance-based compression with chroma preserved) as the setting's stronger mode.
Sliders in Lens > Bloom (HDR) - Advanced, live, default off or subtle; works with every tone mapper.

Test

The glowing pink eye at bloom 0.32 / threshold 2.5 / scatter 1.0: stays pink with preserve on; 0 = today's look.

HDR bloom (Photo Studio / Graphics: Lens > Bloom (HDR)) **desaturates** coloured highlights: a hot-pink glowing eye turns pale lavender with bloom strength 0.32, while the non-HDR glow keeps it saturated. ## Why 1. **Tone mapper shoulder:** bloom adds energy on top of already-bright pixels; with a per-channel tone mapper (ACES Hill) the dominant channel saturates first while the others keep rising, so bright colours drift toward white. 2. **Wide blur veil:** at Scatter 1.0 the bloom is a wide blur that mixes the surrounding colours (purple fur, skin) and lays them over the source, lowering contrast and diluting the hue. ## Wanted: a "bloom saturation preserve" option - Keep the bloom's hue close to its source: e.g. composite the bloom with luminance-based tone mapping for the bloom contribution, or re-saturate bloomed pixels toward the source pixel's hue/chroma (scaled by a strength slider, 0 = current look). - Optionally a hue-preserving tone-mapping path for highlights (luminance-based compression with chroma preserved) as the setting's stronger mode. - Sliders in Lens > Bloom (HDR) - Advanced, live, default off or subtle; works with every tone mapper. ## Test The glowing pink eye at bloom 0.32 / threshold 2.5 / scatter 1.0: stays pink with preserve on; 0 = today's look.

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2026-10-23 22:16:07 +00:00

sky_line added this to the Slipstream project

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sky_line referenced this issue from a commit

2026-10-23 22:59:40 +00:00

#998: HDR bloom saturation preserve (Keep saturation slider + hue-preserving highlights mode)

sky_line referenced this issue from a commit

2026-10-23 22:59:40 +00:00