# When I export from a layered editor to PNG, JPEG or AVIF, what colour tag and transparency does each format record, and what does Krita's exporter do by default?

- id: art_01M5NP4NGQ06ZEKK7K06VQYNCX
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T12, T17 · tags: none
- updated: 2026-10-24T00:49:29.104Z
- url: https://veyrul.com/articles/art_01M5NP4NGQ06ZEKK7K06VQYNCX

PNG records colour via cICP, iCCP or sRGB chunks (cICP takes priority). JPEG carries an ICC profile only in APP2 'ICC_PROFILE' chunks (at most 16,707,345 bytes) and has no alpha. AVIF stores alpha as an auxiliary image and can flag premultiplied colour with a 'prem' reference. In Krita's source, PNG export defaults to keeping alpha, converting to sRGB (forceSRGB) and not writing cICP; JPEG export embeds the profile by default and flattens transparency onto a fill colour.

PNG records colour via cICP, iCCP or sRGB chunks (cICP takes priority). JPEG carries an ICC profile only in APP2 'ICC_PROFILE' chunks (at most 16,707,345 bytes) and has no alpha. AVIF stores alpha as an auxiliary image and can flag premultiplied colour with a 'prem' reference. In Krita's source, PNG export defaults to keeping alpha, converting to sRGB (forceSRGB) and not writing cICP; JPEG export embeds the profile by default and flattens transparency onto a fill colour.

Curator qualifications: Specs and code read 2026-10-22; no file exported. T.81 interchange-scope sentence and the PNG chunk-priority table carried from producer/other batches.

Limitations: Specs and code read 2026-10-22; no file exported. Krita defaults are code defaults; GUI-remembered settings may differ.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://www.w3.org/TR/2025/REC-png-3-20250624/",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://aomediacodec.github.io/av1-avif/v1.2.0.html",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://www.color.org/technotes/ICC-Technote-ProfileEmbedding.pdf",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://www.w3.org/Graphics/JPEG/itu-t81.pdf",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://github.com/KDE/krita/blob/ec6a328c805b397dddbacd48d5e1a950540c0792/plugins/impex/png/kis_png_export.cc",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://github.com/KDE/krita/blob/ec6a328c805b397dddbacd48d5e1a950540c0792/plugins/impex/jpeg/kis_jpeg_export.cc",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    },
    {
      "url": "https://github.com/KDE/krita/blob/ec6a328c805b397dddbacd48d5e1a950540c0792/plugins/impex/jpeg/kis_jpeg_converter.cc",
      "note": "ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] PNG records colour via cICP, iCCP or sRGB chunks (cICP takes priority). JPEG carries an ICC profile only in APP2 'ICC_PROFILE' chunks (at most 16,707,345 bytes) and has no alpha. AVIF stores alpha as an auxiliary image and can flag premultiplied colour with a 'prem' reference. In Krita's source, PNG export defaults to keeping alpha, converting to sRGB (forceSRGB) and not writing cICP; JPEG export embeds the profile by default and flattens transparency onto a fill colour. · locator: ICC Technote: Profile Embedding (JPEG section); AV1 Image File Format v1.2.0, alpha item and item reference types; Krita plugins/impex/png/kis_png_export.cc at ec6a328 L109-126; Krita kis_jpeg_export.cc L71, L81, L167, L184; Krita kis_jpeg_converter.cc L622-634 · source: https://www.w3.org/TR/2025/REC-png-3-20250624/

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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