compositing

Compositing

Pass-aware beauty stack. Subtle grade. Delivery-ready outputs.

When to Use

Final beauty composites from Cycles/Eevee
Grade, glare, vignette, chromatic subtlety
Pass recombination (diffuse, glossy, volume, cryptomatte)
Shot delivery plates

Workflow

Enable passes → Render multilayer EXR (or needed passes)
  → Compositor graph → Grade → FX (glare/fog glow)
  → Output viewer + File Output → Validate exposure

Bloom / glow in Blender 5.x (Python)

EEVEE's built-in bloom toggle was removed in 4.2, and in 5.0 the compositor moved to scene.compositing_node_group. Bloom is a compositor Glare node, and its type is now a menu input socket:

sc = bpy.context.scene
tree = sc.compositing_node_group or bpy.data.node_groups.new("Compositor", "CompositorNodeTree")
sc.compositing_node_group = tree
if not tree.interface.items_tree:
    tree.interface.new_socket("Image", in_out="INPUT", socket_type="NodeSocketColor")
    tree.interface.new_socket("Image", in_out="OUTPUT", socket_type="NodeSocketColor")
rl = tree.nodes.new("CompositorNodeRLayers")
glare = tree.nodes.new("CompositorNodeGlare")
glare.inputs["Type"].default_value = "Bloom"
glare.inputs["Threshold"].default_value = 0.8
glare.inputs["Strength"].default_value = 0.6
out = tree.nodes.new("NodeGroupOutput")
tree.links.new(rl.outputs["Image"], glare.inputs["Image"])
tree.links.new(glare.outputs["Image"], out.inputs[0])

Or run scripts/comp_grade.py with preset="stylized_bloom", which keeps your own nodes.

Recommended Passes

Pass	Use
Beauty / Combined	Base
DiffCol / DiffDir / DiffInd	Relight flexibility
GlossDir / GlossCol	Spec control
Volume	Smoke/fire isolation
Cryptomatte Object/Material	Isolations
Mist	Depth grade / fog

Beauty Stack (Default)

Combined
  → Exposure / Color Balance (AgX-aware)
  → Glare (fog glow / streaks sparingly)
  → Lens distortion (subtle)
  → Vignette (subtle)
  → Output

Grade Rules

Fix exposure before creative grade
Prefer lift/gamma/gain or color balance over crushed curves
Keep skin/product hues plausible
Match reference stills with side-by-side

Outputs

OUT_Beauty_[Shot]
Optional: OUT_Alpha, OUT_CryptoID
Prefer EXR for archival; PNG/JPEG for review

Constraints

MUST DO

Grade on view transform–aware pipeline (AgX)
Keep creative FX reversible in node graph
Document exposure/look settings

MUST NOT DO

Write code or snippets for Blender versions before 5.2, or add version fallbacks: this plugin targets 5.2+, and legacy branches teach users APIs that no longer exist
Crush blacks to hide lighting problems
Over-glare every bright pixel
Flatten multilayer to JPEG as only archive

Scripts

Tested on Blender 5.2 LTS via the official Blender MCP. Run with execute_blender_code (or headless, see the blender-mcp-workflow skill); read the script header for every argument. When the user will paste code into Blender themselves, give them the short runpy call with the absolute path of this installed script and their ARGS. Don't inline or rewrite the script: the tested file is the point.

Script	What it does
`scripts/comp_grade.py`	Build a compositor grade with the Blender 5.x API (scene.compositing_node_group, Group Output, socket-based Glare): bloom, lift/gamma/gain, saturation, lens, pixelate, posterize (`posterize` steps per channel, for 8-bit palettes) and a soft vignette. Replaces only nodes this script created (names starting "SK_"), so a user's own compositor nodes are kept.

import runpy
result = runpy.run_path("<skill_dir>/scripts/comp_grade.py", init_globals={"ARGS": {...}})["result"]

ARGS: preset, vignette (0-1), warmth (-1..1, warm/cool highlights), posterize (colour steps per channel). A "subtle vignette with warm highlights" is {"preset": "clean", "vignette": 0.35, "warmth": 0.4}.

Blender 5.2 compositor facts this script relies on (hand-written graphs usually miss them): node settings are input sockets (Color Balance Type, Blur Size as a 2D vector, Ellipse Mask Size); there is no MixRGB node, use ShaderNodeMix with data_type = "RGBA" (its Factor socket is a NodeSocketFloatFactor).

Reference Guide

Topic	Reference	Load When
Pass Stack	`references/pass-stack.md`	When needed
Grade Presets	`references/grade-presets.md`	When needed
Delivery Outputs	`references/delivery-outputs.md`	When needed