| name | output-format-decision |
| description | Pick the right output file format (PNG / JPG / WebP / OpenEXR / TIFF) per use case based on bit depth, compression, transparency, and consumer support. |
output-format-decision
Purpose
Avoid mismatched output formats (e.g., JPEG for VFX, EXR for web, TIFF for social). Match format to consumer pipeline.
Quick start
- name the consumer
- pick one format per output stream
- pin bit depth + compression + alpha rules
- emit a 4-line config
When to use
- before render
- when consumer requires specific format
- when transparency / HDR / loss tolerance matters
When not to use
- raw modeling without rendering
- 3D exports (use
glb-mobile-performance-budget / glb-animation-handoff)
Trigger phrases
- "PNG or JPEG"
- "do we need EXR"
- "what format for the web"
Prerequisites / readiness
- consumer pipeline known
- color management decision made (
color-management-decision)
Input schema
Required inputs
| Input | Why it is required |
|---|
| Consumer | Drives format choice |
| Color management config | Filmic / sRGB / Linear affects format |
| Transparency required? | Drives PNG vs JPG |
Optional inputs
| Input | Use |
|---|
| File-size budget | Compression decision |
| Multi-resolution requirement | Format-per-tier |
Assumptions to confirm
- The consumer can read the chosen format (verify if non-default).
- Lossy compression is acceptable when chosen.
Output schema
Primary output
A 4-line format record per output stream: format, bit depth, compression, alpha.
Secondary output
- per-output stream rules
- caveats per choice
- evidence label
Evidence / caveat output
Runtime status: Not Run | Attempted | Produced | Verified | Failed | Blocked / Not Run
Artifact status: Not Run | Not Produced | Produced | Verified | Failed
Evidence used: <links, paths, logs, or "none">
Limitations: <known gaps>
Required laws
../../laws/evidence-before-done.md../../laws/non-blender-user-language.md../../laws/no-arbitrary-python-interface.md../../laws/official-runtime-only.md
Official runtime boundary
Decision skill — does not run Blender. Pins format; operator applies to scene render output.
Operating procedure
- Identify consumer + color management config.
- Select format per
references/format-decision-matrix.md.
- Pin bit depth + compression + alpha.
- List caveats.
- Hand off to render evidence.
Decision tree
Web hero (sRGB)?
→ PNG (lossless) or WebP (smaller, modern browsers); 8-bit; alpha if needed
JPEG-only consumer?
→ JPG; 8-bit; no alpha; quality 85-95
VFX / film pipeline?
→ OpenEXR; 16-bit half float; ZIP compression; alpha as channel
Print?
→ TIFF; 16-bit; LZW or no compression; CMYK/sRGB per print prep
Social / mobile (WebP-first)?
→ WebP; 8-bit; alpha optional; quality 85-90
HDR display delivery?
→ PNG-16 or OpenEXR; verify consumer supports HDR display
Playbooks
Playbook A: Web hero PNG
PNG, 8-bit per channel, sRGB color space, alpha if needed. Output ~2-5 MB at 1920×1080.
Playbook B: VFX EXR
OpenEXR, 16-bit half float, Linear, alpha as channel, ZIP compression. Multi-pass support.
Playbook C: Mobile-first social
WebP, 8-bit, sRGB, alpha optional, quality 85-90. Output ~50-200 KB at 1080×1080.
Playbook D: Print
TIFF, 16-bit, sRGB, no compression. Output 5-50 MB at print resolution.
Mode handling
Text-only mode
Format record only.
Runtime-ready mode
After render, verify file actually saved in chosen format + bit depth.
Blocked runtime mode
Format record only.
Validation checklist
Pass / Warn / Fail rubric
| Verdict | Criteria |
|---|
| Pass | Format + bit depth + compression + alpha pinned; matches consumer; caveats listed. |
| Warn | Format pinned but compression / alpha ambiguous. |
| Fail | Wrong format for consumer (JPEG for VFX, EXR for web), missing bit depth, "any format" answer. |
Failure handling
- Consumer unknown → ask once; default to PNG sRGB 8-bit.
- Multiple consumers → pick most-restrictive, render once; or render multiple outputs.
Troubleshooting
| Problem | Response |
|---|
| File too large | Reduce bit depth, increase compression, switch to WebP / JPG |
| HDR data lost | Switch to OpenEXR or PNG 16-bit |
| Alpha disappeared | Verify format supports alpha (PNG / WebP / EXR yes; JPG no) |
| Color shift in delivered file | Verify color management config matches; verify consumer handles sRGB correctly |
Best practices
- Render once per consumer; do not "convert later" unless testing.
- For web: WebP is smaller than PNG with same quality; use it if consumer supports.
- For VFX: always EXR; never JPG / PNG for that pipeline.
- Document the format in render evidence.
Good examples
- "Web hero. PNG, 8-bit, sRGB, alpha if needed. Compression: lossless."
Bad examples
- "Save as PNG." — no bit depth, color space.
User-facing response template
Consumer: <web / VFX / print / social / mobile / GLB>
Color config: <reference color-management-decision output>
Output(s):
<stream>: <format>, <bit depth>, <color space>, <compression>, <alpha>
Caveats: <list>
Limitations: <gaps>
Next: render-export-evidence
Anti-patterns
- "Any format will work."
- JPEG for VFX.
- 8-bit for HDR delivery.
- Lossy compression where archival is required.
Cross-skill handoff
- Color management →
../color-management-decision/SKILL.md
- Render evidence →
../render-export-evidence/SKILL.md
- Engine choice →
../cycles-vs-eevee-decision/SKILL.md
- Resolution →
../resolution-aspect-decision/SKILL.md
Non-goals
- Convert formats post-render.
- Run Blender.
- Compress / re-encode files.
References
references/format-decision-matrix.mdreferences/bit-depth-rules.mdreferences/compression-tradeoffs.md../../docs/skill-system.md
