Resolve FX · Film Emulation · Light

Halation

A dedicated film-halation model for isolating strong highlights and rebuilding them as dye-layer reflections, secondary glow and optional grain — with explicit processing colour space, HDR-aware isolation and detailed control over the final halo.

IsolationDye Layer ReflectionsSecondary GlowBasic GrainGlobal Adjustments

Control map

Halation is built in layers: isolate first, then shape reflections

The most common mistake is to start with Strength and Spread before the source matte is correct. Use the cards below in order: signal space → isolation → dye reflections → secondary glow → grain → final composite.

Where the effect is processed

Processing Color Space

Processing Color Space defines the space in which Halation evaluates brightness and builds its spread. Use timeline is correct only when the timeline really describes the signal at this point in the node tree. If an upstream CST, DCTL or output transform has already changed the signal, an explicit choice can be safer.

Do not choose a space merely because the image looks nicer there
Isolation thresholds depend on the signal state entering this node
Moving the FX across a CST/DRT can materially change the result

Which regions generate the halo

Isolation · Threshold · Normalization

Isolation defines the source of the halation. Threshold sets the lower boundary for which bright regions enter the effect matte. Normalization sets the upper normalisation/clip behaviour of that selection. View Isolated Regions is the essential verification mode: first build a clean highlight source, then judge colour and spread.

Threshold too low = the coloured halo starts leaking into midtones
View Isolated Regions separates matte problems from glow problems
Tune isolation before Strength/Spread

Brightness versus saturation

Film Saturation Level

Film Saturation Level controls how colour information behaves in the strongest halation sources. Blackmagic specifically calls this control useful in HDR: very bright regions still need to generate a readable halo rather than disappearing because of colour behaviour at extreme levels.

Pay particular attention to HDR highlights and saturated practical lights
This is not the frame's general Saturation control
Verify it together with View Isolated Regions

Primary chromatic halo

Dye Layer Reflections

Dye Layer Reflections form the core film-halation character. Strength controls reflection brightness, Gamma changes the glow distribution, Saturation controls colour intensity, and Spread controls extent. Fine Tune Relative Spread exposes separate RGB spread geometry, moving beyond a simple identical blur on all channels.

Strength and Saturation usually benefit from restraint rather than exaggeration
Spread changes extent; Gamma changes distribution character
Fine Tune Relative Spread is for subtle RGB structure, not random colour fringing

Additional broader component

Secondary Glow

Secondary Glow adds a second, broader component around bright detail. Strength and Gamma shape its brightness and distribution, Spread sets the extent, and Filter limits the glow colour. This is not an excuse to turn Halation into generic Glow: the secondary layer should support the primary dye reflection rather than dominate it.

Default Strength is 0 — enable it only when the shot actually needs it
Filter sets the colour character of the secondary layer
A/B it separately from Dye Layer Reflections

Built-in simplified texture

Basic Grain

Append Grain Internally enables a simplified Film Grain subset directly inside Halation: Strength, Size, Softness and Saturation. Blackmagic explicitly recommends a separate Film Grain instance after Halation when more detailed grain control is required. Internal grain is useful for a quick coherent look, but it does not replace the full Film Grain FX.

Do not stack internal grain and a separate Film Grain unintentionally
For delivery-sensitive grain, prefer the dedicated Film Grain FX
Judge grain at 100% and in playback

Final composite control

Global Adjustments · Blend

View Glow Alone displays only the generated effect and greatly speeds up tuning. Reduce Highlights reduces unnecessary brightening of the source itself, keeping the effect closer to its edges. Aspect Ratio stretches the halo/grain horizontally for anamorphic character, while Detail Loss defocuses underlying detail. Global Blend is the final wet/dry trim.

View Glow Alone is the best debug mode for Strength/Spread/Filter
Reduce Highlights helps preserve the source instead of simply bloating it
Trim Blend only at the end

Halation vs Bloom vs Glow

A warm edge artifact is not the same thing as a generic highlight glow

Blackmagic describes Halation as subtle light scatter and reflection back through motion-picture film dye layers, commonly appearing as a fine red/orange tinted glow around high-contrast bright regions. Film Look Creator deliberately offers a simplified Halation module; the standalone FX is the detailed tool.

Practical rule: if the viewer notices a red outline before noticing the image, the effect is probably too strong. Good halation usually reads as a film characteristic, not as a visible preset.

Production workflow

Six passes from a clean highlight source to believable film halation

Confirm the signal state

Before touching the halo, confirm what colour space actually reaches the node. Processing Color Space and isolation thresholds depend on this state.

Build the isolated source

Enable View Isolated Regions and tune Threshold, Normalization and Film Saturation Level until only the highlights that should generate halation remain.

Shape dye reflections

Use moderate Strength and Saturation, then set Spread and Gamma. Only after the main halo works should you consider Fine Tune Relative Spread.

Add secondary glow only if needed

Use the second glow as support for broader light spill. If it becomes the visual subject, you are probably building Glow rather than halation.

Decide who owns grain

Use Append Grain Internally for a quick integrated texture, or keep it off and use the dedicated Film Grain FX later for full control. Avoid accidental double grain.

Check glow alone, then final composite

Use View Glow Alone to find halos in the wrong places, tune Reduce Highlights/Detail Loss, then return to the image and trim Global Blend while watching real playback.

Common failures

Most bad halation is really a bad source matte or too much spread

Everything gets a red outline

Cause: Threshold is too low and the isolation matte includes midtones or ordinary edges.

Fix: Use View Isolated Regions and raise Threshold until only genuinely bright sources survive.

It looks like generic glow

Cause: Secondary Glow or Spread is dominating the dye reflection structure.

Fix: Back off the secondary layer, reduce spread, and make the primary chromatic edge the defining feature.

Highlights become swollen and milky

Cause: Strength is excessive and the source itself is being brightened too much.

Fix: Lower Strength and use Reduce Highlights so the halo remains edge-biased.

The look changes when moved across CST

Cause: The same thresholds and spread are now operating in a different signal domain.

Fix: Keep Halation at a documented pipeline position and set Processing Color Space to the signal that actually reaches it.

Highlight scatter as a film-emulation model

Halation: the signal-level model

The most useful way to think about Halation is not as a red Glow but as a two-stage model: Isolation first builds a source from strong highlights, then Dye Layer Reflections and Secondary Glow convert that source matte into controlled chromatic scatter. If the source matte is wrong, no amount of later Strength/Spread tuning will make the result believable.

Blackmagic describes Halation as an emulation of subtle light scatter, reflections and analog bloom reflecting back through the dye layers of motion-picture film, typically appearing as a fine red/orange halo around bright high-contrast regions. Current Resolve exposes a dedicated Processing Color Space, making the effect colour-space-aware: Isolation levels and spread must be judged in the real signal state at that node.

There is no universal rule that Halation must always sit before or after the output CST. The same Threshold selects different pixels in scene-referred and display-referred signals. Lock placement and Processing Color Space deliberately. Film Look Creator contains a simplified Halation module; the dedicated FX is for detailed isolation, dye reflections, secondary glow, grain and global controls.

Use it when

a subtle film-style chromatic edge around strong practical lights, speculars and reflections
a dedicated film-emulation look node when Film Look Creator's built-in Halation is too limited
controlled HDR/SDR highlight scatter with explicit isolation verification

Choose another tool when

you need a generic neutral broad glow/bloom without film dye-layer character
source highlights are already clipped/flattened so severely that isolation cannot build useful structure

Control → signal meaning → verification

Layer	What it means	How to verify
Processing Color Space	Defines the processing space for Halation; the default Use timeline inherits the timeline/project context.	Verify against the actual signal state entering the node, especially after CST/DCTL/DRT.
Threshold	Lower Isolation boundary — which bright regions are allowed to generate halos.	Use View Isolated Regions: midtones and ordinary edges should not flood the matte.
Normalization	Upper-point/normalisation behaviour of the isolated source before reflections are generated.	Check that a broad highlight range is not collapsing into one identical white mass.
Film Saturation Level	Controls saturation/desaturation behaviour in the strongest source-matte regions; Blackmagic specifically notes its usefulness in HDR.	Compare saturated LEDs/speculars and very bright HDR highlights in isolated view.
Dye Layer · Strength / Gamma	Strength sets the brightness of the primary reflection layer; Gamma shapes its glow distribution.	Use View Glow Alone + A/B; the source itself should not become the dominant blown-out patch.
Dye Layer · Saturation / Spread	Saturation sets halo colour intensity; Spread sets its spatial extent.	Excessive values quickly turn a film cue into an obvious digital red glow.
Fine Tune Relative Spread	Exposes separate RGB reflection distances for finer chromatic structure.	Keep channel separation subtle so it does not read as chromatic aberration.
Secondary Glow	An additional broader glow layer with its own Strength/Gamma/Spread and Filter.	Build it up from zero and verify that it supports rather than masks the primary halo.
Basic Grain	A simplified Film Grain subset inside Halation.	Avoid accidental double grain with a dedicated Film Grain FX; inspect at 100% in playback.
Global Adjustments	View Glow Alone, Reduce Highlights, Aspect Ratio and Detail Loss control final halo integration.	Inspect the glow alone, then the composite; Aspect Ratio is especially obvious on circular practicals and anamorphic intent.
Global Blend	Final wet/dry mix of the calculated Halation against the source.	Use it after isolation/geometry are correct, not as a substitute for tuning them.

Production workflow

01Identify the signal state and choose the correct Processing Color Space.
02Enable View Isolated Regions and tune Threshold/Normalization/Film Saturation Level.
03Return to normal view and build Dye Layer Reflections from conservative Strength/Saturation values.
04Set Spread/Gamma; enable Fine Tune Relative Spread only for a real chromatic-shaping need.
05Add Secondary Glow and/or internal Grain only after the primary halo works without them.
06Use View Glow Alone to inspect stray regions, tune Reduce Highlights/Detail Loss/Aspect Ratio, then trim Global Blend.

Diagnostics: symptom → cause → fix

Red halos appear on skin and midtones

Likely cause: Threshold is too low or Processing Color Space does not match the signal state.

Fix: Inspect the isolated matte, raise Threshold and confirm the processing space.

Halation looks like generic Bloom

Likely cause: Secondary Glow/Spread is dominating the Dye Layer Reflections.

Fix: Return Secondary Strength toward zero, reduce Spread and restore a fine chromatic primary halo.

Bright sources become swollen white patches

Likely cause: Strength is high, Reduce Highlights is too low, and isolation is too broad.

Fix: Lower Strength, raise Reduce Highlights and tighten the source matte.

The effect changes dramatically after a CST

Likely cause: Halation moved into a different signal domain while keeping the same thresholds.

Fix: Lock node placement and retune Processing Color Space/Isolation for the actual input.

Node placement

A practical approach is to keep Halation on a dedicated look/finishing node after the base balance and look shaping, when bright structures are established. Blackmagic's Colorist Guide shows a dedicated HAL node in the LOOK layer after Look/Contrast and before Vignette. This is not the only valid order, but it is a useful documented starting point. When using a separate Film Grain instance, the manual recommends placing it after Halation.

Scopes / validation

View Isolated Regions and View Glow Alone are more important than conventional scopes for first-pass tuning because they expose the internal source/effect matte. Waveform helps reveal swollen highlights and clipping; RGB Parade is useful when Fine Tune Relative Spread or chromatic bias becomes excessive. Judge final intensity on calibrated monitoring and in real playback.

Managed-pipeline warning

Halation is a colour-space-aware spatial effect. In RCM/ACES, Use timeline can be correct when the timeline truly represents the working signal at that node. In manual YRGB with CSTs, or after a DCTL/output transform, verify it explicitly. Do not duplicate the output transform or move Halation across a DRT expecting identical isolation: the mathematical source matte changes.

Do not confuse the roles

Halation versus the neighbouring Color FX

Color Space Transform

explicit conversion between colour-space/gamma descriptions, including tone/gamut mapping

Halation

Halation is built in layers: isolate first, then shape reflections

Processing Color Space

Isolation · Threshold · Normalization

Film Saturation Level

Dye Layer Reflections

Secondary Glow

Basic Grain

Global Adjustments · Blend

A warm edge artifact is not the same thing as a generic highlight glow

Six passes from a clean highlight source to believable film halation

Confirm the signal state

Build the isolated source

Shape dye reflections

Add secondary glow only if needed

Decide who owns grain

Check glow alone, then final composite

Most bad halation is really a bad source matte or too much spread

Everything gets a red outline

It looks like generic glow

Highlights become swollen and milky

The look changes when moved across CST

Halation: the signal-level model

Use it when

Choose another tool when

Control → signal meaning → verification

Production workflow

Diagnostics: symptom → cause → fix

Node placement

Scopes / validation

Managed-pipeline warning

Halation versus the neighbouring Color FX

Primary references used for this technical layer

Practical Halation questions

Is Halation the same as Bloom or Glow?

Should Halation go before or after the output transform?

When should I use View Isolated Regions?

Do I need Append Grain Internally?

Why does the effect become ugly so quickly?

Keep halation, bloom, grain and the base film look conceptually separate

Flicker Addition

Film Look Creator

Film Grain

Split Tone