xGlow Fuse

xGlow applies a physically based bloom: it extracts the highlights above a threshold, runs a multi-scale blur and composites the result back over the original image. Closer to the physical behavior of a real lens than the native Glow (which is more "stylized" / mathematical).

Performance: thanks to the GPU, it can process 4K in real time on a decent GPU. The native Fusion Glow is CPU-bound and much slower at high resolutions.

• Install it through Reactor: search for "xGlow" in the package browser, click Install.
• After installing and restarting Fusion, the Fuse shows up in Tools > Fuses > xGlow.
• Source code available on GitHub ("xFuses" repository or similar, depending on the maintainer).

Native Fusion Glow

Basic bloom, several methods. CPU-bound, can be slow in 4K. Good enough for stylized glow / motion graphics.

xGlow

Physical GPU bloom. Multi-scale (several stacked blur levels), precise threshold, realistic light distribution. For film / VFX quality.

Rule: fast motion graphics → native Glow. Live action / quality film work → xGlow.

• Image (orange) - the image to process.
• Effect Mask (blue) - optional.

Film bloom on HDR:
HDR Render → xGlow (Threshold = 1.0, Spread = 50, Mix = 0.3)
          → MediaOut

Stylized neon look:
Neon footage → xGlow (Threshold = 0.7, Spread = 100,
                     Saturation Boost = 1.5,
                     Mix = 0.6)
            → MediaOut

Subtle filmic glow:
Beauty plate → xGlow (Threshold = 0.85, Spread = 30, Mix = 0.15)
            → MediaOut

Multi-scale stack:
Plate → xGlow (small Spread, low Mix)
     → xGlow (medium Spread, low Mix)
     → xGlow (large Spread, low Mix)
     = nuanced multi-scale bloom

Threshold (default: 0.8)

Luminance threshold above which the bloom is extracted. Pixels below it do not contribute. 0 = bloom everywhere, 1 = highlights only.

Spread (default: 50)

Size of the bloom in pixels. Low = tight halo, high = wide, diffuse halo.

Mix (Strength) (default: 0.5)

Strength of the bloom mixed into the result. 0 = invisible, 1 = max.

Quality (default: Medium)

Quality / performance preset. High = more samples, more precise, slower.

Saturation Boost (default: 1.0)

Multiplies the saturation of the bloom for a stylized effect. 1 = neutral, >1 = boosted saturation.

Multi-Scale (default: On)

Computes the bloom at several stacked scales (higher quality but slower).

• Film bloom on HDR - an HDR 3D render with extreme highlights: xGlow gives a convincing physical bloom.
• Neon / sci-fi stylization - low Threshold + high Spread + Saturation Boost = a neon, holographic, futuristic look.
• Subtle filmic enhancement - a low Mix (0.1-0.2) on live action = a film touch without an overdone look.
• Better lens flares - an existing lens flare with xGlow on top = a more convincing halo.
• Multi-pass rendering - several xGlow nodes stacked with different Spreads = a subtle multi-scale bloom.
• Performance in 4K - when the native Glow crawls, the GPU-based xGlow lets you keep iterating in real time.

• Threshold on HDR footage - with HDR, values >1 are normal. A Threshold of 1.0 really isolates the highlights.
• Keep the Mix subtle - start at 0.2-0.3 and raise it gradually. Too much = a washed-out look, not pro.
• Multi-Scale on for realism - without multi-scale, the bloom is too uniform and looks artificial.
• GPU required - xGlow needs an OpenCL / CUDA compatible GPU. On CPU only, it does not work or is very slow.
• Combine it with a native Glow - native Glow for stylized highlights, xGlow on top for a subtle physical bloom. They complement each other.
• Side-by-side comparison - to validate a switch from the native Glow to xGlow, use a split screen to see the difference visually.
• Document the version you use - xGlow is versioned. Note the installed version in a Sticky Note for team consistency.
• For really extreme cases (linear HDR with hyper-saturated speculars), also consider a native Resolve Tonemap before the bloom.